The American Annual Cyclopaedia and Register of Important Events of the Year, 1861-1865, vols. 1-5. New York: Appleton & Co., 1868.

Navy of the United States, 1862

NAVY, UNITED STATES. 1862 The organization of the Navy Department of the United States embraces a secretary and two assistants; a bureau of navy yards and docks; a bureau of construction and repairs; a bureau of provisions and clothing; a bureau of ordnance; a bureau of medicine and surgery; a bureau of steam engineering; a bureau of equipments and recruiting; a bureau of navigation, embracing the naval observatory and hydrographical office.

The officers of the navy, by an act of Congress of July 16, 1862, are divided into nine grades, taking rank according to the date of commission in each grade, as follows:

1. Rear-Admirals,

2. Commodores,

3. Captains,

4. Commanders,

5. Lieut.-Commanders,

Their rank as compared with officers of the army is ae follows:

6. Lieutenants,

7. Masters,

8. Ensigns,

9. Midshipmen.

Rear-Admirals to rank with Major-Generals.

Commodores                       Brigadier-Generals,

Captains                              Colonels,

Commanders                       Lieutenant-Colonels,

Lieut-Commanders             Majors,

Lieutenants                         Captains,

Masters                               First Lieutenants,

Ensigns                               Second Lieutenants.

The number of officers of each rank, at the close of the year, was as follows:

Active list.           Reserved list.          Retired list

Rear-Admirals 4                                          9  

              acting 5

Commodores 16            16

Captains         89           10                          22

Commanders 90            11                          7

Lieutenant-Commanders. 144

Lieutenants 104             17                         6

The vessels of the navy building and in service, and the number of guns carried by them, and the class to which they belonged, were on November 1, 1862, as follows:

STEAMERS:

                          No. of vessels.     No. of Guns.

Side-wheel steamers 102  ……………533

Screw steamers ……114  ……………672

Iron-clad steamers 53  ……………..266

Steam gunboats and rams 13  ………67

Total  282  ……………………….1,537

SAILING VESSELS.

Ships and frigates 12  ……………894

Sloops-of-war 21  ……………….846

Mortar fleet 19  …………………..56

Ships, barks, brigs, &c. 50 ………194

Total 102    …………………….1,400

The vessels in service have formed the following squadrons: West Gulf squadron, 59 vessels; West Indies, 8 vessels; East India squadron, 3 vessels; Mediterranean, 6 vessels; Pacific squadron, 5 vessels; South Atlantic blockading squadron, 63 vessels; North Atlantic blockading squadron, 65 vessels; Western Flotilla, 79 vessels; East Gulf squadron, 24 vessels; Potomac fleet, 21 vessels; coast of Africa, 1.

For the operations of the navy in contest with the Confederate forces, see NAVAL OPERATIONS, AND ARMY OPERATIONS.

The most important subject before the Government and people of the United States relative to their navy respects the iron-clad vessels. The operations of the Government during the year, with the principles that have been developed, and the improvements which have been made relative to these vessels, so far as they are allowed to be known, are presented in the annexed pages.

IRON-CLAD, OR ARMORED VESSELS.—The ground occupied by either army in an engagement in open field being of uncertain character and extent, and liable to continual change, it results that here no definite system of defence is practicable, and that a land battle is chiefly waged, on both sides, in the way of offensive operations. On the contrary, in naval engagements, and those carried on from within fortifications, the area and objects against which the assault is directed are limited and well defined; in effect, the ground (so to speak) of the defending party is for the time not only small but unchangeable. However simple and obvious this distinction, it is radical, and one that is even now developing consequences of Page 605 the utmost importance. Thus, it is in the case of ships and forts alone that the problem and means of defence become equally essential with those of offence; and that the former, like the latter, arc of a highly definite and special character, and only to be advanced through careful study of the mechanical and other conditions involved. In fact, in the case of ships, it is most distinctly seen to be true that, when the defence can no longer be improved so as reasonably to keep pace with increasing efficiency and power in the means of assault, the necessary alternative must be the abandonment altogether of naval warfare, or the comparative worthlessness, at the least, of any resort to it Now, since the early part of the present century, a steady increase has been going forward in the caliber of ordnance and in its available power, that is, in other words, in the penetrative and, generally, the destructive effect of projectiles; while the course and prospects of a naval engagement have been, in a particular manner, changed by the introduction of the so-called Paixhan guns, which throw shells of great weight and at a velocity sufficient for penetrating the wooden sides of the ordinary ships of war, preparatory to spreading destruction and conflagration within them. It is these facts that have forced upon military authorities of the time the specific problem of defence, especially for all classes of war vessels, and so urgently that within the past three years it has become the paramount question in connection with the practice of warfare. Under such circumstances, the subject can, of course, only be presented as one in a state of progress—its results being not merely still undecided, but for the present beyond even the reach of conjecture.

The Necessity of Armor Recognized.—A ship or boat, then, being a definite point or object of attack, and the penetration and destructiveness of solid and hollow shot having been gradually and very greatly increased, the inevitable consequence was that, sooner or later, wooden war vessels must become too vulnerable to leave even a reasonable chance of their withstanding a well-directed fire. And, this point once reached, the idea of seeking a more efficient resisting material in some metal, and naturally in iron, must, by a necessity just as inevitable, have presented itself; so that it becomes a matter of slight importance at what precise time, or by whom, the suggestion of such a change was publicly made. By some authorities the proposition is accredited to Mr. John Stevens, of New Jersey, its date about the year 1811; by others, to Colonel Paixhan, of the English army, some ten years later.

Among the earliest systematic experiments with a view to the substitution of the resistance of iron for that of wood in the sides of ships, were those made by English authorities in the year 1840, and a few years following, in the way of firing upon targets representing a portion of the side of an iron ship, as ordinarily constructed. As a result, it was found that the thin plates of such ships, when struck by projectiles that pierced them, crushed into fragments, which were scattered with peculiarly destructive effect; so that ordinary iron ships were wholly unsuitable for war purposes. A definite proposal for constructing shot-proof iron floating batteries was, about the year 1852, entertained by the United States Government; but the results of experiments made with a view to that end being deemed unfavorable, the project was, for the time, abandoned. Still, the subject was more or less under discussion in this country, and in Franco and England. It is said that, many years previously, an imperfect attempt had been made at mailing the English ships which took part in the battle of Algesiras (1801), and that, subsequently to that occasion, M. Montgery, of France, had published several memoirs on the subject. The project having become, in that country, in a degree forgotten, attention was again called to it during the war between Franco and Russia, by the circumstance that wooden ships were found incapable of withstanding a skilfully-directed fire from near land batteries. The French emperor directed, in 1854, that experiments should be made with a view to the protection by iron armor of ships of a draught rendering them suitable to be employed in an attack on Cronstadt. Upon a renewal of some experiments discontinued about 15 years before, the conclusion was reached that, in order to afford protection against the round shot then in actual use, a thickness of 1/10 metre = 3.937 inches, was required. Of the armored boats or floating batteries hastily constructed in accordance with these views, and which, from the weight of the plates and the depth of water they drew, were incapable of speed, and even of independent navigation, three that were taken to the French fleet, then before Kinburn, participated in the attack, October 1855, on the forts at that place. Though struck by very many 24-lb. balls at about 600 yards, the armor of these boats was not actually pierced, but only somewhat deeply indented; but considerable injury was done by shots which entered the portholes. Some British batteries of like construction did not arrive so as to take part in the action.

In the year 1854, experiments in relation to iron armor were also made in England; in these, a target, consisting of a wood backing covered with wrought-iron plates of 4 ½  inches thickness, and intended to represent the side of an armored ship, was found to be indented at 400 yards by 82-lb. solid shot and 8-inch and 10-inch hollow shot, to depths respectively of l ½ , 1, and 2 ½  inches; , while 68-lb. solid shot, fired with 16 lbs. of powder, penetrated the plates, splitting them especially in the line of the bolt-holes, which were about 1 foot asunder. In France, a new interest was awakened, by the comparative success of its trial at Page 606 Kinburn, in the subject of iron armor; and, in experiments in which 60-lb. balls were fired at several yards' distance, and with a heavy charge of powder, upon plates of the thickness already adopted, it was found that the balls sufficed to break the plates, though they did not go through them. The results, however, differed much with differences in quality of the iron; and, if not previously admitted, it now became evident that, for resistance to shot, a somewhat soft iron is preferable to an iron having great hardness, with its attendant brittleness. The experiments undertaken in the United States had tended to show that, for guns of the largest caliber then in use, although 4-inch plates, well backed with solid timber, were likely, for a time, to resist piercing by shot thrown from considerable distances, yet nothing less than 6 inches of iron plating could be relied on to render a ship practically invulnerable. This result was discouraging, in view of the fact that the complete armoring of a ship with 6-inch plates appeared to involve a weight which no vessel can carry without great sacrifice of speed, and a loss even of capacity for open-sea service.

The next step in the construction of iron-clad ships (French, vaisseaur en cuirass, or navires cuirasses), was the building of La Gloire in France (1860), and of the Warrior in England (1861). The armor of these ships is described in the preceding volume of this Cyclopaedia. Sir Howard Douglas has lately asserted in substance that both these ships are failures, so far as sea-going qualities, speed, and the stability requisite for successful firing upon a heavy sea, are concerned. Both appear to be, with combined armament and armor, overloaded, and owing to the lowering, in consequence, of the meta-centre (centre of pressure of the liquid displaced) to near the place of the centre of gravity, both these ships roll in a heavy sea with quick and considerable movements, so that the gunner's aim in such cases becomes extremely uncertain. Moreover, while La Gloire has not exceeded 11, in place of the 13 knots an hour anticipated, and the "Warrior at sea not more than 12, the latter can carry but 9 days' coal, and in long voyages must often rely on tenders or sails. Apparently, therefore, these ships, and, probably, the others armored by the two nations upon respectively the same patterns, are not, on the score of their capacity for distant expeditions and aggressive warfare, very greatly to be dreaded.

The Revolving Turret, or Cupola.—But while ships may possibly be so armored as to be in the main nearly impregnable to an enemy's fire, yet their portholes remain subject to the entrance of shot, and that in proportion to the size that must be allowed for properly working and pointing the guns; while the lateral sweep in this way secured is always limited, and the entire ship must often be manoeuvred in order to bring the guns into the desired line. If, however, instead of the ordinary casemate or broadside arrangement, the guns can be placed within a protecting structure which can be revolved into any required line of fire, all the difficulties connected with the management of the guns, the exposure incident, and the continual effectiveness of the ship's armament, vanish or are reduced to their minimum. Such is the idea of the revolving turret or cupola, and such the objects to be attained through its use. The original invention of this important addition of the last few years to the means of naval warfare, has already been claimed on behalf of three persons, Captain John Ericsson of New York city, Mr. Theodore R. Timby, of the State of New York, and Captain Coles, of the British navy. In the year 1854, Captain Ericsson forwarded from New York to the emperor Napoleon a communication (dated September 26) in reference to a new form of armored vessel for naval attack, designed by him—the plan embodying many of the features of the "Monitor," presently to be referred to, but especially those of a deck rising but a few inches out of water, and of a turret amidships to contain one or two large pieces of ordnance, and to be capable of being revolved so as to bring the guns into any desired line of fire: the shape of this turret, however, was that of a dome, or half a hollow globe, the ports being at one side. The receipt of the communication was duly acknowledged by the emperor. Captain Ericsson further states that the idea of a revolving tower for ordnance upon land is very old; but that the thought of placing such a structure upon a ship was original with himself, having been conceived many years before the time of the communication above mentioned. Captain Coles, in a letter to the (London) " Times," April 5,1862, states that the idea of building impregnable vessels was suggested to him by his experience in the Baltic and Black seas, in 1855, and that toward the close of that year he had a model for such vessels made, in which he proposed to protect the guns by a stationary "shield" or "cupola." Notwithstanding official neglect, he persevered, producing in March, 1859, drawings of a "shield fitted with turntables;" and in December, 1860, he published an account, with drawings, in which the platform of the shield was to be turned by manual power. Mr. Timby constructed, in 1841, a model of a revolving tower for land fortifications, pierced with one or two tiers of portholes, and to contain several guns, these to be fired in succession as they were brought by the revolution in line with the object of attack. A larger model was exhibited in many places in 1843, among others in New York, notices of it appearing in the "Evening Post" of June 13, of that year, and in the "Herald," during the same month. It will be soon that the purposes and principle, on the one hand, of the Ericsson and Coles turrets (accounts of which will be given farther on), and on the other, of that of Mr. Timby, are wholly distinct: with the former, the revolution of the tower is not Page 607 the object sought, only so far as needful to point the guns upon the enemy; in the latter, the revolution is indispensable, as well as nearly continuous—a condition that must involve important difficulties in practice. So long as it revolves properly, the Ericsson turret serves to keep an enemy continually under lire, in spite of changes of position. In this way, two guns become—supposing no necessity of delay from their heating—equal in effective force to at least eight mounted on stationary carriages.

Earliest American Iron-clad Vessels.—" It so happens," Admiral J. A. Dahlgren very appositely remarks in his Report supplementary to the Report of the Secretary of the Navy, November 22, 1862, "that circumstances impose on England and France the necessity of grappling with the most difficult solution of the problem [that of armoring ships], their shores being washed by the deep waters of the ocean; therefore their iron clads must be more than mere floating batteries, and be possessed of the best nautical qualities. 'With the United States the case is, happily, different—the depth of water on the coast being generally adapted to vessels of light or moderate draught, and only a few of our ports being at all accessible to heavy iron clads like those of France and England. The solution of the question is, therefore, in its immediate requirements, comparatively easy and inexpensive for us. Vessels of the Monitor and Ironsides class are likely to serve present purposes sufficiently well, and to give time to obtain, from our own and the experience of others, better data than can now be had for advancing to a more perfect order of vessels." The facts here stated in respect to the general character of the coast navigation, Atlantic and Gulf, of this country, as also the great extent to which naval operations may require to be carried on in navigable sounds, bays, and rivers, but which are not always of great depth, have been kept in view in all the earlier attempts here made in the way of armoring vessels—with the single exception, indeed, of the first of them all, the Stevens Battery, the proposed draught of which is 21 feet. (For a full description of this battery, as well as of Captain Ericsson's first iron-clad battery, the Monitor, the plan of which was one of the three first adopted by the United States Government, in 1861, see the preceding volume of the Cyclopaedia.) Of these three patterns of iron-clad vessels, and the draught of which ranged from 10 to 13 feet, all were in fact mainly new in conception, differing from the earlier French and English batteries in being intended to realize independent navigation and fair speed, and from the Gloire and "Warrior styles in being of much leas dimensions, while also nearly or quite completely mailed. The most original in principle of the three, and the one that has come to be regarded as peculiarly the American style of iron-clad vessel, was the Monitor—a name that is now employed as distinctive of the growing class of vessels involving the same general construction. The Monitor was built at the Continental Works, Greenpoint, L. I., by Mr. J. F. Rowland, under the direct supervision of Captain Ericsson, and delivered to the Government, March 5, 1862. The vessels completed in accordance with the other two of the three contracts, were, for that with the firm of Merrick & Sons, Philadelphia, the New Ironsides, and for that with S. C. Bushnell and Co., of New Haven, Connecticut, the Galena. The experiments preceding the inception of the Monitor had already determined that, since very hard and brittle plates are proportionally more liable to crack, and very soft ones to be simply punched or penetrated, for armoring in the modes thus far adopted, neither steel or hard cast iron on the one hand, nor copper or the softest wrought iron, on the other, should be employed, but in fact an iron possessing fair forging and rolling qualities, and having along with moderate hardness also a high degree of absolute strength or tenacity. In the case, however, of armor applied, not in a single thickness or plate, but in a succession of thinner plates (laminated armor), a harder iron or steel is said to be used with advantage. It will be remembered that the armor of the upper hull of the Monitor consisted of 5 inches of rolled iron (1-inch) plates; that of the turret generally of 9, and that of the deck of 2 inches of similar plating. Of course, though in England there is an apparently open avowal and discussion of all information acquired in respect to penetration of projectiles and qualities of armor indicated, it is probably true that in all the leading countries now interested in this question, as is evident in the case of the Government of the United States, there is nevertheless a degree of reticence in respect to important results, and especially as to certain points in the construction, armament, and working of iron-clad vessels. Hence, there are portions of information in regard to these subjects which can only become public after the lapse of a few years, or under a condition of national questions different from that which now exists.—An account of the experiments in the way of testing the relative capacities of the most recent and improved ordnance and iron armor, with the bearing of the results on the questions of thickness, kind, quality, and extent of armor protection for vessels, as well' as of the modes in which the plates are prepared for being applied, will be given farther on.

The First Class Monitors (Smallest Size).— The course and result of the engagement between the Monitor and Merrimac, in Hampton Roads, March 9, 1862, having established the suitableness and success of the Ericsson form of battery, both for purposes of defence (at least, against guns of the power there employed) and of attack, orders were speedily issued by the U. S. Government for the construction of 10 similar batteries, one or more of which, indeed, must have been at the time already commenced.

Page 608 The following are the vessels included in the orders referred to: Name.               Where built.                    Date of launching.

1. Passaic Greenpoint,    L. I                           April 31, 1862.

2. Patapsco Wilmington, Del                          October 1, 1862

3. Nahant Boston, Mass                                  October 6,  1862

4. Montauk       Greenpoint, L. I                     October 9,  1862

5. Nantucket... .Boston, Mass                         December 6, 1862

6. Lehigh         Chester, Penn                         December, 6, 1862

7. Sangamon,   Chester, Penn                         December 6, 1862

8. Catskill Greenpoint,    L. I                          December 6,  1862

9. Weehawken. Jersey City, New Jersey,   December 6, 1862

10. Camanche, Jersey City,                        December 6,  1862

These batteries were built and armored substantially in accordance with the plan of the original Monitor, but of somewhat larger dimensions, and with some important modifications introduced from the start or when near their completion, as suggested by further experience in working vessels of a style so unusual. Exteriorly, they show an upper and broader portion of hull, heavily armored and nearly vertical, and a much shorter, as well as narrower lower portion of hull, not armored: the form of the actual hull (of iron), however, appears only from within, being somewhat modified from the shape usual in vessels of like size, and not unaptly compared to that of the half of an egg-shell cut lengthwise. Their decks are mainly clear, and intended to rise but from 18 to 30 inches above the water. They are rated at 844 tons burden; and they have each 1 turret, revolving, and a total armament of 2 guns, now, generally, of 11 and 15 inches caliber. Their construction being substantially the same, a description of one of these batteries will serve for the whole class.

The Passaic has a length of upper hull equal to 200 feet, width 45 feet, total depth 12 feet, draught of water when laden 10 ½  feet. The lines of the hull are finer than those of the first Monitor, and the buoyancy and speed greater. The hull of the vessel is first built of J-inch iron plating, fastened upon a frame of angle iron, of 6 inches width by 3/4 -inch thickness. The broader upper portion of the hull commences at about 5 feet below the deck, that is, 3 ½  feet below the water line, by a sort of horizontal iron shelf, upon which is first built up the wood backing for the armor, consisting of solid oak, to a thickness of more than three feet, and braced with iron. Over this is applied the armor, consisting of 5 thicknesses of wrought-iron plates, each 5 feet in length and width. In addition to and beneath this, for a distance of 50 feet from the bow, in the Passaic, are inserted a succession of wrought-iron stringers 4 inches thick, the two combined being equivalent for this part of the boat to 9 inches of solid armor, and giving it immense strength for use as a ram. The deck beams are of oak, 24 inches apart, 12 X 12 inches at the middle, and 12 X 10 at the ends. Over these is a pine planking 8 inches deep; and upon the whole two thicknesses of 1-inch plating. The hatches are of wrought iron, and let in flush with the deck; in action they are closed with covers of like material, secured below. "Within, the vessel is strengthened forward of the turret bulkhead by three rows, and aft of the bulkhead by one row, of stanchions of 23 x 4 bar-iron, fastened with 1-inch bolts; and there are six water-tight compartments, formed by £-inch plates properly secured, and between which communication is furnished by means of doors. The turret has an internal diameter of 21 feet, height 9 feet. Its sides are composed of 11 thicknesses of 1-inch plating, each in 20 vertical sections, but so put on that at any part in the entire thickness but a single joint occurs. It rests on a flat ring of composition metal, 12 inches wide by 1 ½  thick, and provided at its inner edge with a vertical flange of like thickness, and 2' inches in height. The pilothouse, with a total diameter of 7 feet, 4 inches, rests on the top and middle part of the turret, the general framework of the top consisting of stout forged iron beams alternating with others resembling railroad bars, these being respectively three inches apart. Over these, on the part of the top not occupied by the pilothouse, is a covering of ½  -inch wrought-iron plates, these being perforated at certain parts with holes 1 inch in diameter, for the supply of air to the turret and hull. The pilothouse, 6 feet in height and in interior diameter, is formed of 8 inches of plates, and is pierced with 8 lookout holes, each giving a horizontal range of vision of 45°, so that together these render every part of the horizon visible from within. The turret has 2 portholes near together; and the armament is an 11-, and a 15-inch Dahlgren gun. The portholes are closed with ponderous port stoppers, each weighing more than 6,000 lbs.; one man can readily open these preparatory to firing, and close them immediately afterward. The engines, 2 in number, built at the Delamater Iron Works, have cylinders of 40 inches diameter, and 22 inches stroke. There are 2 boilers, of Martin's plan, each 9 feet 3 inches in height, and 12 feet 6 inches long, with 3 furnaces. The propeller is of cast iron, 12 feet in diameter, and of 16 feet pitch.

The hull and armor-shelf of this battery (save about the upper 2 feet of height) being, when the vessel is afloat, below the water, and the unarmored portion of the hull being in effect removed 5 feet within the sides, and descending in all but a few feet below them, it results that no shot fired upon the battery can reach this lower portion without first having penetrated the armor and timbers, or in the rare case of coming at a very small angle with the water, having its force quite expended before striking. Moreover, the armor-shelf or platform, which projects no more than 5 feet at the sides, is extended at the ends so as to project at the bow full 16 feet beyond the boat proper or hull, and at the stern 25 feet. The effect of this arrangement is to give complete protection to the anchor and capstan within the bow, and the propeller and rudder at the stern. A propeller well opens from the deck through the aft overhang, while through the fore overhang is an anchor well, 5 feet in diameter, and so arranged that the anchor—a patent form, with 4 flukes—can be taken up through it.

Among the important changes from the plan of the first Monitor introduced generally in the new batteries, the following should be particularly named: 1. While the former had the sides of its lower hull sloping at an angle of 80° to the vertical, and a flat bottom, the latter have more nearly an ordinary midship section, with an ordinary rise of flow, and a round bilge. 2. While, in the former, the turret received the support of but a single bulkhead running across the vessel, the turrets of the latter receive support from 4 bulkheads, 2 transverse and 2 longitudinal, and which are heavily braced with "angle bars." 3. The overhang at the stern is greatly reduced in the new batteries, so that in a seaway they are correspondingly less subject to strain on this account. 4. The new batteries only are provided with a heavy iron-plate chimney, which rises about 6 feet above the deck. In these, accordingly, the retraction of the chimneys through the deck during an action is not required. 6. In them, also, the air supply is more safely and effectually obtained through the top of the turret, the blowers, driven also by blower engines of larger size, being placed just beneath the turret flooring, and acting to force air into the boiler room and other parts of the hold; The guns within the turrets, moreover, do not usually require sighting, since the direction of fire can be found and kept by means of the "turret sight," fixed parallel with the guns before a small opening in the wall.

Besides the 9 new Monitor batteries first ordered, others involving further variations of plan or dimensions have been commenced at different places. In January, 1863, the Osage, one of these, was launched at St. Louis, Missouri. This boat is 180 feet in length, having 1 turret and 2 11-inch guns, the deck oval and at the edge only 12 inches above the water, and with an oval pilothouse at the stern. The Camanche was constructed in sections, to admit of being taken apart for transmission to California, for protection of the coast of which country she was designed. Another fleet, of 8 Monitors of the first class, and of dimensions differing not much from those of the previous ten, are now in course of construction.

Improvements in Working the new Monitors. —In the first Monitor, the guns were run out for firing, so as to project through the portholes; and they were, of course, exposed for the moment to increased danger of being struck and disabled. Besides, it was becoming desirable to substitute guns of 15-inch for those of 11-inch caliber; and while, when this change was decided on, some of the turrets were already bored with portholes of the original dimensions—for 11-inch guns—it was desirable also, in view of saving the strength of the turret and diminishing risks of entrance of the enemy's missiles, to keep the portholes as small as possible. All the ends indicated could be subserved at once, if it were practicable to discharge the guns within the turret. To this important problem, involving such particulars as the means of reducing greatly the recoil of the piece on firing, as also the question of the effect of the concussion and reverberation on those within the turret, Capt. Ericsson diligently applied himself. An apparatus for the guns was devised, the details of which have not been made public, but which was intended to control the action of the piece in the moment of firing, especially in the way of allowing of all needful recoil within the limits of the turret. November 15, 1862, a short trip was made up the Hudson river, with the Passaic, for the purpose of experiments with the new apparatus, among those on board being Admiral Gregory, general superintendent of iron-clad vessels, and chief engineers Stimers, Lawton, and Robie. Three hollow shot weighing each 330 lbs. were successively fired, in the direction of the Palisades on the west bank of the river, from the 15-inch gun within the turret; the first, with a charge of 20 lbs. of powder, the other two with a charge of 35 lbs. each; and the recoil was found to be brought wholly within control, being 17 inches for the first shot, 8 ft. 10 in. for the second, and 2 ft. 8 in. for the third. It appears that the recoil is diminished by means of a friction apparatus of peculiar form; and the excessive recoil of the second shot was duo to the circumstance that the screws or "compressors" in the apparatus had not been properly tightened beforehand. No inconvenient effect from the concussion was experienced by those within the turret. Thus the entire feasibility of discharging the piece within the turret was demonstrated; and a few days subsequently orders were sent from Washington directing that the turrets of all the Monitors be at once completed with portholes of the original dimensions.

Again, in view of the ease with which the great guns now employed on these batteries, and especially as fitted with the new apparatus, can be served, it results that a very great economy in the requisite force of gunners, and in expense is secured. Thus, while 25 men have been found insufficient to serve a single Armstrong gun on shipboard, its weight only 14 tons, it is here true that 6 men serve efficiently and with ease the two guns of the Passaic, the 15-inch one weighing 42,000 lbs., and with a charge of 85 lbs. of powder, throwing a 450-lb. solid shot, or a shell of the weight above mentioned. The total complement of officers and men for each of these Monitors is less than 100.

Among other improvements in working the Monitors, and, as well as the preceding, severally by plans of Captain Ericsson's invention, are those by which the bed of the turret is rendered water tight; the arrangement for using the compass, when not in action, free from the Page 610 interference due to the attraction of the iron mass of the battery itself; and the consequent plan of steering by a mirror. The leakage occurring under the turret in the first Monitor, when her deck was washed by a heavy sea, was a serious inconvenience. Means have now been devised by which, while the turret has the' requisite freedom of movement, the leakage beneath it is wholly prevented. In the new arrangement of the compass, this is raised far above the disturbing influence of the iron turret and deck; while, by means of mirrors suitably placed, the movements and position of the needle are rendered perfectly visible to the helmsman at his place within the pilothouse.

In reference to the sea-going qualities of the Monitors, repeated experience has shown that though in a storm or heavy sea the waves continually break or roll over their decks, yet they possess remarkable stability and steadiness of movement; and since they are now rendered water-tight, save for the water, easily removed by the pumps, that may enter by the top of the turret, they are safe against all casualties except such as may arise by grounding on rocks or springing a leak, and to which all vessels are exposed. Again, since the boiler fires need no longer be interfered with by influx of water, and the boilers and engines must continue to perform more successfully in a tempest than those of vessels which pitch and roll more, it follows that their chances of weathering a storm are even better than the average for vessels generally, and that they may safely undertake sea voyages of any length for which the coal they carry will suffice. On the 20th and 21st of January, 1863, the Weehawken outrode successfully and without inconvenience, while on her way to Hampton Roads, one of the severest gales known to our coasts. The speed of these batteries has not exceeded about 8 knots an hour.

Up to the time of the attack (April 7, 1863) on the forts in Charleston harbor—full particulars of which cannot be included in this article—the new batteries had taken little part in actual service. The Montauk was engaged during at least three hours in the attack on Fort McAllister, on the Ogeechee river, February 27, 1863; and while her shot told with great effect on the loose sand works of the fort, the 40 shot received upon every exposed part of the battery herself, and consisting of rifle bolts and 8 and 10-inch solid shot, occasioned no actual damage to her, but served to show the possession of invulnerability in a very high degree. The 5 or 6 shot which struck the deck glanced, leaving only slight furrows in the upper plate. The shot striking the side armor of the battery (5 inches) were smashed, and left on the armor dints of about i the area of their greatest section, and an inch in depth. Upon the turret (11 inches of plates) and the pilothouse above it (8 inches), the results were similar, save that the dints were not so deep. 'Within, no perceptible effect of the blows remained, except in the pilothouse, where 7 of the bolt-heads, which had been screwed up too tightly, were broken off by the concussion of the shot striking the plating, or perhaps by the slight recoil of the plates after concussion, and so were projected from the wall into the enclosed space. There was nowhere any sign of penetration. The 15-inch gun was handled with ease; and no annoyance resulted from the discharge, the concussion, or the smoke, nor from the impact of the enemy's shot, except that the blast from the guns returned through the eye holes of the pilothouse, so as to prevent observing the effect of the practice. In fact, but a part of the shot of the Montauk were directed against the fort, her principal fire being aimed at the ship Nashville, lying under its protection. This vessel she destroyed; and the instance is the first in naval history in which a war vessel, safely disregarding the heavy fire of fortifications, has effected the destruction of her antagonist lying under cover of their guns. After the action, the immense weight of the turret (160 tons), which is supported upon a central shaft, had caused a slight settling; but the shaft being keyed up from below, the turret again revolved freely.

In the attack at Charleston, above referred to, the New Ironsides, flagship, the Monitors Weehawken, Passaic, Montauk, Patapsco, Catskill, Nantucket, and Nahant, and the Keokuk, were engaged. The conflict lasted in all about two hours, the iron-clad vessels carrying all together but 32 guns, and firing only 151 shot. During nearly three quarters of an hour, they sustained the converging fire of the Cumming's Point battery, Forts Moultrie and Sumter, and Battery Bee, these probably mounting in all not less than 800 guns, which threw 8, 9, 10, and 11-inch round shot and shell, and 5 and 6-inch rifled shot, some of the latter evidently from guns of the latest Whitworth pattern—tho whole number of shot supposed about 3,500. It has been stated that, as a result of the fire of the fleet upon Fort Sumter, several holes were knocked through the northeast face of the wall, one or more of these apparently 3 feet across. While the number of guns in the fleet was very small, it was practically reduced about one half, by the failure to bring the casemate guns of the New Ironsides to bear upon the fort, beyond the extent of a single broadside. The firing commenced and ceased at about 1,300 yards; during the period in which it was at close quarters the range varied from 300 to about 600 yards. In the conflict, the Passaic was hit 58 times, one of the shot hammering down the plating at the point struck at bottom, so as to cause it to bind, and interfere with the turning of the turret; while the gun-slides on which the 11-inch gun were placed were also sprung. The Weehawken was struck 59 times; the Montauk 20; the Nantucket 51; the Catskill about the same number of times; the Patapsco, 40, and the Nahant about 80 times. The armor of the Page 611 Monitors, including the plating of the decks, be known as those of the second class; three turrets, and pilothouses, was considerably of these, the Mahopac, Manhattan, and Tecum, dinted; but nothing like fracture of the seh, at Jersey City; two, the Catawba and armor or turrets occurred, and nothing apTippecanoe, at Cincinnati; the Canonicus at proachiDg to penetration. In one or more in Boston, and the Manayunk at Booneville, Kentucky stances a shot ploughed its way, while glanc These are to have each one turret, and carry ing, nearly or quite through the thinner platwithin this 2 15-inch guns. Thus, the weighting of the deck. Nor was the propulsive maof their battery alone will (as in case of some machinery of any of these vessels damaged. The of the first-class Monitors also) be about only casualties within them occurred by the 60 tons, and they will discharge at once 900 snapping off, in the manner before referred to, lbs. of iron—a weight quite equal to that of  some of the bolt-heads inside the pilot the whole broadside of an old-fashioned war house of the Nahant—these not having been vessel. The armor of these vessels is to be 9 covered, as they were in most of the Monitor inches of plating, their turrets and pilothouses fleet, with sheet-iron guards: four of the offi11 inches" thick, the increase in weight being cers and men of the Nahant were wounded by allowed by the fact that they are to be of 18 these bolts, one of the men mortally..

Loss of the Original Monitor.—The loss of are each to be of 1,564 tons burden, and to carry this now world-famous battery, which occur4 guns. Their armor will also be very thick, red off the coast of North Carolina, December 31, and the intention is to make them of unusual 1862, during a violent gale which commenced strength. on the previous day, although an accident The Onondaga, built at New York, is of 1,250 that appears to call for regret from national tons burden, and carries 4 guns. This also, considerations as well as for the painful sacriknown as the Quintard battery, is a modificafico of life attending it, could not serve to overtion of the Ericsson pattern, having 2 turrets, throw the conclusions already expressed in length 226 ft., breadth 48 ft., depth of hold 13 respect to the sea-going qualities of the Monift., and the construction of which is expected tor batteries; and especially so, since the 10 to give unusual buoyancy. She has two screwnew vessels of the sort, built under less urpropellers, for use in manoeuvring, as in turning gency in respect to time, were also constructed on her centre, &c. expressly with more regard to fitness for navThe Dictator and Puritan.—These are two igation and sea service. The Monitor was in large batteries and rams, also of the Ericsson tow of the Rhode Island, and, the water which pattern, the former building at New York, the entered the hold gaining so as to stop the latter at Greenpoint, L. I. The former of them working of the engines, at about 1 30 p. m. of is to be 320, the latter 341 feet in length, and the 31st, she went down. Four of her officers each of 50 ft beam. The vertical sides are to and nine men, as well as eight men of the be 6 ft. in depth, armored with plates and Rhode Island, were lost. wrought-iron slabs to a thickness together of A New Life-raft, devised, or at least com10J inches, this being backed with 4 ft. thick plated, since the sinking of the Monitor, has ness of solid oak. The turrets, of which the been supplied to several of the new Monitors, Dictator has one, the Puritan two, are to be as well as, of course, to other vessels of the absolutely invulnerable to the 450-lb. shot of navy. This raft consists of several water15-inch guns, and for this purpose to be of 15 tight hollow air-filled cylinders of canvas inches thickness, the outer 6 inches of plates, coated with gutta percha, pointed at the ends, then 5-inch slabs, and within these 4 inches of and each of the cylinders having projecting plates. The propulsive power will also be unflanges furnished with eyelet holes, through usually great; each ship having two engines, which the several cylinders are lashed to with cylinders of 100 inches diameter and 4 ft. gethcr. Each cylinder is composed of 3 thickstroke. The modified Martin's boilers employnesses of the canvas, its flanges, by doubling ed are to have 85,000 ft. of heating surface, and lapping of the edges, of four. For rowing, with 1,180 ft. of grate surface. The propellers throe light boards or stretchers can be placed are Ericsson's, 21i ft. in diameter, and of 32 ft. above the whole. The very great buoyancy pitch. The guaranteed speed is 16 knots, or of this raft was shown in trials in which every near 19 miles an hour. The armament is to available foot of room upon it was crowded consist of the most powerful wrought-iron guns with sailors standing closely together; the raft that can be made. The plates and armor string showed no sign of sinking under such a burden; ers meeting at the bow will form an iron wedge and when but ordinarily loaded it can be rap21 inches thick at the base, and terminating in idly propelled by oars or sails. a nearly sharp edge; this wedge being sustained The Second and Third Class Monitors.—In by the entire length and depth of the armor of January, 1863, there were building seven new the ship will constitute a ram of the utmost Monitor batteries of 1,034 tons burden, and to possible strength.

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The New Ironsides. —This frigate, at the time of its launching the largest American iron-clad vessel afloat, is built somewhat upon the plan of the English "Warrior. Her frame is of white oak, averaging in thickness at top of the sides 20 inches. Her armor is partial, extending from 4 feet below the water line upward to the spar deck, and horizontally the length of that portion of the gun deck containing her armament (170 feet), besides a belt of 7 feet width at her water line, and running entirely around, thus leaving a part both at bow and stern unprotected. The bulkheads, however, at each end of the gunroom are bomb proof. The armor is of single plates, 4 inches in thickness. The ports, 8 on a side, are closed, each by means of 2 wrought-iron plate3 which fall together at the recoil of the gun. The total length of hull is 232 ft.; breadth of beam, 57 ft. 6 in.; depth of hold, 25 ft.; draught of water at deep load line, 15 ft.; tonnage by measurement, 2,486 tons; displacement, 4,120 tons; estimated weight of armor, 750 tons. The vessel is bark-rigged, with short bowsprit, and no jib boom. Besides 2 200-pounder Parrott rifled guns, and 4 24-pounder boat howitzers, she carries a proper battery of 16 11-inch Dahlgren guns, the united weight of which is 234,800 lbs., while they throw at one broadside a weight of metal, shell, equal to 1,100 lbs., or solid shot, equal to 1,600 lbs. There are 2 horizontal direct-acting engines, diameter of cylinder 50 inches, stroke 30 inches, with surface condensers of 8,000 sq. ft. condensing surface; and, to supply these, 4 horizontal tubular boilers, with a heating surface of 8,450 square ft.; the estimated consumption of coal in 24 hours being 48 tons 840 lbs. The propeller is a single composition screw, with 4 blades, diameter 13 ft., mean pitch 16 ft., length 29 inches. With her masts (three in number) and spars in place, she can also carry quite a press of sail. Her bow is fitted with a heavy ram, securely fastened. From a circular pilothouse upon the spar deck the commanding officer communicates directly with the gun deck, and with the helmsman below. A defect of this ship is said to be in want of speed. In the attack on the forts at Charleston, in moving against the tide, she refused to obey her rudder, becoming quite unmanageable. Although she remained at about the longest range named above from Fort Sumter, and did not long present her side, so as to receive the enemy's shot direct, it is stated that some of the thick plates composing her armor were cracked.

The Galena.—This, one of the earliest completed of American iron-clad vessels, was built by Messrs. Mason and Fish, at Mystic, Connecticut, after designs by Mr. Julius Patterson. Her length is 208 ft., breadth of beam 36 ft., depth 12 ft. 6 in.; she is of 1,000 tons burden, and pierced for 18 guns. Her hull is of the best white oak, strapped with iron; and her sides, above water, slope inward at an angle of about 80°. Her armor is applied in the form of iron bars, 24 ft. in length and 3 inches in width, these successively overlapping each other by 3 part of their width, and fastened to the wooden frame by screw bolts: while over this is an additional plating of 1-inch iron, also secured with like bolts. The gun deck is about 7 ft. in height, and has ports for 18 guns. The upper or spar deck is covered with thin plate iron, but said to be gun proof. The ports are closed by large pendulum shutters, which part in the middle, so that only the muzzles of the guns need protrude, and the gunners are comparatively safe. The round pilothouse has 5 inches thickness of plating. The armament consists of 11-inch guns and 100-pdr. rifles. In the combat with Fort Darling, on the James river, the plating of the Galena did not successfully resist a well-directed fire of large solid shot.

The Roanoke.—This vessel was originally a double-decked war frigate, and with the Merrimac also, one of a class of 5 steam frigates built in 1855. Having proved singularly unfortunate and expensive in her original trim, she was, by order of the Government, in 1862, razed or cut down flush with her gun deck, preparatory to plating, the object being to convert her into a powerful iron clad, exposing but little of her hull above water to an enemy's fire. This vessel was armored, and received her additional engines, at the Novelty Iron Works, New York; her armor, consisting, like that of the Ironsides, of single or solid iron plates, in this case mainly of 4 ½  inches thickness, having been forged at the "Franklin Forge" of Messrs. Tugnot, Dally & Co., of the same place. The plating, backed with 80 inches of oak, extends 4 ft. below the water line, and the whole length of the hull. The deck is covered with 5-inch plates, placed one upon the other, so as to break joint where the edges meet; the joints come neatly together, but with a small space left to allow of expansion and the natural working of the ship. The plates are secured by countersunk bolts to the deck beneath. Over the hatch surrounding the smoke pipe where it issues from the deck, is a heavy grating of wrought iron, 1 inch thick by 7 inches deep, so that projectiles striking this must glance off without injury. The form of hull is that of sea-going vessels generally, and the deck will be without guards. The portion of the rudder post usually exposed will be covered by a strong wrought-iron hood, which will also protect the propeller from shot. There are three revolving turrets, of the new Monitor dimensions and pattern —11 thicknesses of 1-inch plate—and each pierced for two guns; two of these being forward, and one abaft the centre. The parts of the deck over which the turrets are severally placed are strengthened with circles of oak timber beneath, nearly 12x12 inches, these, again, being supported at regular intervals by stanchions of like dimensions. Each central turret Page 613 shaft rests on an immense cast-iron step, provided with a wrought-iron key, and a composition seat or have upon which this is to advance: the key being driven, the ways on which the turret revolves are thus relieved of a portion of its weight. Besides the blowing engines, and the auxiliary ones for moving the turret, &c, the vessel is propelled by the engines used in her when a wooden frigate—2 trunk engines, with 80-inch cylinders, and 86 to 42 inches stroke; the whole are supplied with 4 Martin's boilers and a large auxiliary or donkey boiler. The battery of the Roanoke consists of—forward turret, 1 15-inch smooth-bore gun and 1 250-pdr. rifle gun; middle turret, 1 11-inch and 1 15-inch smooth-bore gun; after turret, 1 15-inch and 1 200-pdr. rifle gun. This is said to be the heaviest battery ever yet put together on a single ship.

The Roanoke's bow is also furnished with a powerful ram. To form this, the forward plates project some feet beyond the stem, and farthest at about the water line. At the extremity, a solid piece of iron is inserted and firmly secured between the plates projecting from the two sides; and the angular space between this and the bow proper is filled in with solid timbers firmly bolted together. The Roanoke, now armed, is said to be as yet the most impregnable and formidable vessel of the navy. She is expected about the 20th of April, 1863, to take her position off the Narrows, as the permanent guardship of New York harbor.

The Keokuk.—This vessel, also named, from Mr. C. W. "Whitney, her constructor, "Whitney's Battery, was built in New York. The Keokuk is a two-turret ram, length 159 ft. 6 in., breadth 36 ft., depth of hold 13 ft. 6 in., draught 9 ft. Her hull is of ½ -inch rolled plates, the sides, above the water, sloping in at an angle of 87°, to prevent a square hit by the enemy's shot. The sloping sides, and the deck higher at the middle of its length, in this and a few other iron-clads of similar form above water, have gained for them the name of " turtles." Without going into all details of construction, it may be said that the peculiarity of the Keokuk's side armor consists in its being formed of alternating bars of iron and strips of yellow pine, each 4 inches thick by 1 wide, over the whole of which there are applied 2 continuous f-inch plates: it is claimed that this arrangement will give the strength of 5 ¼  inches of iron, without its full weight. The turrets do not revolve. Each is to contain an 11-inch gun, which is to be turned, as required, to different portholes. The turret armor is constructed like that of the sides, its total thickness being 5 ¾  inches; but the turrets, also, are sloping, being 20 ft. in diameter at base, 8 ft. 8 inches high, and 14 feet at top. A strongly made ram, 10 ft. broad at the hull, 3 J inches thick at the front and foot, and 5 feet long, projects from the bow. By means of bulkheads, water-tight compartments are formed Within. These can be filled in 15 minutes when it is desirable to depress the vessel in the water during an action, and emptied again by the pumps in 40 minutes. The Keokuk has two engines, each of 250 horse power, and two propeller screws, by means of which she can be manoeuvred with great facility.—In the action at Charleston, occurring since the above was prepared, the Keokuk was struck by 90 shots: of these, 6 went through the after turret, 3 through the forward one, 7 through the smokestack, and several through the side armor, some near the water line. One Whitworth steel-pointed shot remained sticking in the wall of the after turret. The vessel sank the next morning, and was to be blown up.

The Dunderberg.—This, intended to be a highly impregnable and, in all respects, formidable iron-clad war vessel, is now building, after plans designed by Mr. W. H. "Webb, and at his shipyard, New York. Her extreme length will be 878 ft., breadth 68 ft., depth of hold from the main deck 23 ft., tonnage 7,000, and she will be propelled by engines of 5,000 horse-power. The bow of this vessel, for a length of 56 ft., will be a solid mass of timber, and the frame and decks, in fact, the remainder of the hull throughout, will be constructed of an almost incredible weight of timber of the largest size, and braced within with iron bars diagonally crossing each other, of dimensions of 6 by 7/8  inches. The sides proper of the vessel, 2 ft. thick, are strengthened by an additional 2 ft. of timbers without. Before applying the armor, a projecting angle or " hip" is built on over the 4 feet of wood already mentioned, and entirely round the vessel, the greatest thickness occurring at the level of the main deck, and being there 7 ft. in all: from this level the hip slopes in at an angle of 68° with the vertical, until it terminates at the sides, about 6 ft. below water line. This sloping portion is completely coved with armor, of course set at the angle just named. Upon the main deck, for 170 ft. in the middle part of the vessel's length, a casemate of long octagonal form is built up, its sides sloping upward and inward at an angle of 47°. This, so far as it extends along the deck at the sides, forms a single angle with the slope of the sides below; and it rises by its entire height—7 ft. 6 in. in the clear—above the level of the deck at bow and stern. The sides and ends of this casemate are plated in the same manner as the sides of the hull, with 4|-inch solid plates. The deck plating and that upon the casemate roof is of J-inch plates. The total weight of armor will be about 1,200 tons. The main deck, and so the hip, is at 6 ft. above the water line. Upon the casemate roof will be erected two revolving turrets of great strength, and each to contain two guns of the heaviest caliber. There will also be at least 10 large guns in the casemate, the port sills being 8 ft. above the water line. There will be two rudders, so that in case one becomes disabled the other can be useful; and both the rudders, along Page 614 with the immense propeller screw, will be protected by a strongly built overhang at the stern, its length about 17 ft., its width on either side of the propeller shaft, 12 ft., while, as a further protection, the sides of the overhang also curve or project downward. The solid bow, with its plating, will constitute the vessel a very powerful ram, the destructive force of which will be greatly augmented by the high speed, of 15 knots an hour, she is intended to possess; while, on the other hand, the hip will afford protection by first receiving the shock of a ram that may attempt to run her down. The Dunderberg is expected to be a highly efficient sea-going vessel. She will, probably, not be completed until about the beginning of the year 1864.

The Italian iron-clad frigates, Re d’ Italia and Clotilda—the first-named already built and the last in process of construction—are also built by Mr. Webb, and at his shipyard. The Re d' Italia, now being armored with 4.j-inch plates at the Novelty Iron Works, is a 40-gun propeller frigate, 294 feet long, and furnished with a ram. Five other Italian iron-clad frigates are building in France and England.

The Benton, Gunboat.—This is one of the fleet of gunboats hastily improvised for service upon the Mississippi and its affluents, in the early period of the war. She was constructed of two hulls joined side by side,— length 186 ft., total breadth 74 ft.—these hulls being sealed up between with 4-inch oak plank. The entire upper part of the hull, to several feet below water line, was then plated with ½ -inch iron, securely bolted on. The Benton draws 4 ft. of water, and, besides having a bomb-proof bow, she is divided into 40 water-tight compartments, so that if her bow were shot away she would still float, and her gunners and men would be protected as before. The wheels are between the two single hulls, toward the stern, the wheel houses being, for ordinary missiles, shot proof. The sides, above water, slope inward at an angle of 45°. Her armament consists of 18 8 and 9-inch guns. In operations on the Western rivers, this and other gunboats of its class have, in a general way, performed satisfactorily, their fire being very efficient, and themselves, in but rare instances, thus far, disabled or sunk.

The Essex, Gunboat.—This iron-clad, which has figured quite conspicuously in river operations at the West, has a length of 205 ft., beam 60 ft., depth of hold 4 ft. 6 in. Her hull is nearly submerged, and her casemates have the unusual height of 17 ft. 6 in. The wood-work of her forward casemate is 39 in. thick; of the side casemates, 16 in., and of the pilothouse 18 in. thick. Over all these parts is a continuous layer of rubber, 1 inch thick. The iron plating bolted on over this is, upon the forward casemate and pilothouse, 1 3/4 inches thick, that upon the side casemates ¾  inch thick. This vessel is also divided into 40 water-tight compartments, and upon her sides are hips, or false sides, intended first to receive and break the blow of an enemy's ram. Her armament consists of 3 9-inch Dahlgren guns, 1 10-inch shell gun, 2 50-pdr. rifles, 1 long 32-pdr., and 1 24-pdr. boat howitzer.

The Tuscumbia, Gunboat.—This vessel, recently completed, is one of the largest of the Western fleet. Her length is 182 feet, beam 70 feet, depth of hold 8 feet, draught, when laden, 5 ¾  ft., tonnage 980. The sides of this vessel are plated with 3-inch, and the deck with 1-inch wrought iron; the plates over the batteries or gun rooms will be 6 inches thick forward, and 4 aft. Her timbers are very strong, her build staunch, and outfit complete. A bulwark of iron, loopholed for musketry, is placed around her guards. Her engines and machinery were made by Messrs. McCord & Co., St. Louis. The main engines, two in number, with 30-inch cylinders, of 6 ft. stroke, impel 2 powerful side wheels; while 2 other engines, with 20-inch cylinders and 20-inch stroke, work the two screws. Her armament is 3 11-inch Dahlgren guns, in battery, forward, and 2 100-pdr. rifled guns, in battery, aft. The magazines, or the hold, can, by the pumps, be completely flooded in a very brief time; while, as an addition to her armament, she has an apparatus for throwing, to a distance of 200 ft., a stream of scalding water.

Other Gunboats and Rams.—Certain ironclads building at Pittsburg will have a length of 175 ft., beam 50 ft., depth of hold 7 ft.; the bottoms will be flat, the hull rising considerably out of water will present somewhat the form of a coal barge, though with sides less vertical, and greater sharpness toward the bow. The hull will be plated with 4-inch iron to 2 ft. below the water line. There will be 1 turret, its sides of 6 inches of plates. Each boat will be propelled by 4 engines, and will carry 2 large guns, her draught, loaded, being about 5 ft. These boats are intended solely for river service.

The Indianola is one of a new class, of gunboat and ram combined, intended for river service, and to have a light draught and high speed. Her wooden sides are 3 ft. thick, and her armor, over this, three inches of iron. The wheel, wheel house, and roof are bomb proof. The Choctaw, in many respects of similar construction, though of different form above water, will carry a heavy armament, and, with her high speed, will constitute a formidable craft.

Recent English and French Armored Vessels. —The French navires cuirasses thus far completed having, with the exception of the iron frigate La Couronne, wooden hulls over which the armor is applied, are like some of the American armored vessels correctly described as being "iron clad;" but a large proportion of the English vessels of the class under consideration being really iron ships with armor in addition, these are more properly described as "armored Page 615  iron," than as iron-clad vessels. In fact, a strict classification of the new vessels, based on materials employed and mode of combination in the construction of their hulls, has not yet been attempted; and while the (American) Roanoke and Dunderberg are strictly iron-clad vessels, in the Keokuk and some others, the character of hull is more nearly or exactly entitled to the description of "composite."

The only English counterparts, thus far, of the Warrior (described last year), are the Black Prince, also of 6,039 tons, and the Defence and Resistance, each of 3,668 tons burden. Their armor is, briefly, that of the sides only through about one half the length amidships, and from the upper deck to 5 ft. below the water line. In the Achilles, also of 6,039 tons, the same extent of armor is applied, along with the important addition of a belt of armor extended, for a space reaching a little above and below the load water line, entirely about the remaining portions at bow and stern; the purpose of this being to guard against the unfavorable accident of penetration "between wind and water." The Defence and Resistance carry each 14 casemate guns: their speed is slow. The Achilles has a casemate 200 ft. long, carrying 26 guns. The Northumberland, Minotaur, and Agincourt, each of 6,621 tons, and 390 ft. length, are to be protected over their iron shell, from stem to stern and from the upper deck to 5 ft. below water line, with a 9-inch wood backing and 5 ½  inches of armor, forming a casemate the whole length of the vessel, and carrying 40 broadside guns. All these are iron ships. The Prince Consort, Royal Oak, Royal Alfred, Ocean Triumph, Caledonia, each of 4,045 tons, and 277 ft. long, are wooden frigates previously in part constructed, and now being converted into iron clads; the extent of their armor will be the same as in the preceding (Northumberland) class, and their armament 82 68-pdrs. The Hector and Valiant, each of 4,063 tons, and 275 ft. long, and armored to the same extent, with the singular deficiency of a short distance at the water line near the bow and stern, will carry each 80 casemate guns. It may be added that many, if not all, of the vessels here described will carry in addition 2 or more Armstrong swivel guns, fore and aft.

The vessels of the three last-named classes are thus very heavily laden with armor; and to avoid this condition, it appears, Mr. E. J. Reed, Secretary of the Institution of Naval Architects, was first to suggest the plan of confining the armor to a short casemate amidships, with shot-proof bulkheads at its terminations fore and aft, and with this additionally a belt of armor a few feet wide carried round the remainder of the vessel at the water line. The ships recently, if not now, building expressly upon his plans, are the Enterprise and Favorite; the former of 990 tons, 180 ft. long, with four guns; the latter of 2,168 tons, 220ft. long, with 8 guns. In the Enterprise, the hull below the base of the central battery is of wood, hut protected by plating with iron the deck situated at level of the top of the water-line belt of armor. The remaining upper works of the ship are of iron; while from the square central armored portion or tower the guns can be fired both athwartships, and fore and aft. Of the Favorite, the entire hull is of wood; and to protect it from being fired by shells, the portion of the sides above the armor belt and before and abaft the central battery arc plated, but more thinly, with iron.

Besides the English vessels now described, there are three or more classes furnished with Captain Coles' revolving "shields" or "cupolas," which correspond in purpose with the turrets of our iron-clad vessels, with the peculiarity, however, that (like those of the Dunderberg) they have sloping sides. The Royal Sovereign, three-decked line-of-battle ship, cut down to her lower deck, and completely plated with iron, her length being 830 ft., has 5 of these cupolas, each intended for 2 110-pdr. breechloading Armstrong guns. The Prince Albert, also a razed ship and of the same length, has 6 cupolas, each to receive two similar guns. These formidable batteries are intended for coast defence. The class of iron vessels carrying two of Coles' cupolas have a length of 175 ft., beam 42 ft., depth 24 ft., draught 17 ft. All the vessels with cupolas, though not as high out of water as the casemate vessels, still rise above the water line higher than do those of the Monitor classes. Like the American, turret-carrying vessels, they have no masts, and a mainly clear deck. Very recently, Captain Coles urges that vessels of this sort should be masted; and he has prepared a model of such a ship with 4 masts, having a lengthened hull, and with one shield removed. To obviate the objection arising from risk of shooting away rigging, he proposes to make the masts of iron tubes rigid enough to bear the strain of the canvas, when standing entirely alone, i. e., without shrouds or stays.

Of French armored ships, the original La Gloire class, 4 in number, and built of wood, have a length of 255 ft., and are completely clad with 4|-inch solid armor. There are 10 other French vessels of similar construction but of somewhat larger dimensions. The Solferino and Magenta, also of wood, and about 270 ft. in length, are plated on the same general plan with the American New Ironsides, and the English Enterprise, namely, with a central battery or casemate amidships at which the plating extends from the upper deck to a few feet below the water line, and a belt of armor a few feet in width at this line about the rest of the ship. They will carry each 26 guns.

The Manufacture and Application of Armor Plates.—Since it is for the present admitted that the armor must possess qualities to be found only in a good wrought or malleable iron, its production has thus far been confined to the two modes of rolling and hammering. Page 616 The relative advantages of these two methods are still only in part decided. In this country opinion and practice have favored the making of thin plates by rolling, since in such plates homogeneity of structure and uniformity of strength are less likely in this way to be sacrificed, and the manufacture is much more rapid; while for thick plates, in order to secure close interlacing of the fibres and uniform tenacity, working under the hammer has been preferred. The thin rolled plates are formed from bar iron or blooms, produced in the usual manner. The blooms for the thick plates are usually produced from " scrap iron," selected, but of mixed description, piled in fagots of a convenient size, brought to a welding heat in a furnace, and reduced under the steam hammer to a solid mass. Several of these blooms are then laid in a pile, four or more layers deep, and successively crossing each other in length, conveyed in this condition into a large furnace in which they are again heated until the whole becomes highly malleable, and under the steam hammer are then welded into a portion of a plate; and additions are made in like manner to one end of this, until the material requisite for a single plate has been in this way united. The plate so produced can be of almost any size desired, and it is finally brought to more uniform condition and surface by one or more heatings followed by working under the hammer. The plates of the Roanoke, forged and built up in this way, were of a usual length of 12 to 15 ft., and width of about 3 ft., their thickness generally 4 ½  inches, and their weight 4,000-7,000 lbs. Such a plate is a sort of oblong plank of iron: other plates of irregular outline required for special parts of the ship's sides are shaped by appropriate machines.

These plates are next drilled for the bolts, and those requiring it are also bent to fit the part to which they are to be applied. By means of "templets," or facsimiles, in thin board, marked with spots corresponding to the holes already bored in the wooden body, or drilled (as the case may be) in the parts of the iron hull upon which they are to be fastened, the successive courses of plates, numbered in their proper order, are then marked for the bolt-holes and drilled; after this the holes are usually " countersunk," in order that the bolt head may enter so as to stand even with the outer surface. The plates are finally bent to the shape they may be required to have, by the action of powerful hydrostatic presses. The required curvature is readily given to the plates for upright turrets, by placing them one at a time between a curved bed upon the upper surface of the movable platform of the hydrostatic press, and a fixed frame of like curvature above, and forcing the plate upward until it is shaped between the two, as in a mould. These plates are, at different works, bent either cold or heated. The plates for the sides of the ship require to be bent to a great variety of curves, and the expense of preparing a corresponding number of moulds is obviated by employing an upper and a lower " die," each consisting of a series of strong iron bars, these being severally capable of being raised or depressed, as required, and at either end, by the action of stout screws which fix their positions. Above the upper die, which is movable, is a heavy iron casting to give it weight, while the lower die is stationary. A templet, representing any required plate, being placed between the two dies, the upper and lower sets of bars have their ends raised or lowered by the screws, until each bar exactly fits upon its own part of the templet; and the upper die being then raised to some distance, and the templet removed, the plate, already heated to a highly soft and ductile condition, is placed upon the lower die; the upper being then let fall, the weight with which it is loaded suffices at once to bring the soft plate to the required shape ; or any slight departure from this is corrected by tightening the bars, at points where it is requisite.

In England, the two modes of producing the single thick plates under the hammer, and by the rolls have each their advocates. The hammered plates of the Thames Iron "Works are thus made: The best scrap iron being selected and cleaned, is piled, heated, hammered into a bloom, and then rolled into bars 6 inches broad by 1 thick; these bars are cut up, piled and again hammered into a slab; several of these slabs are laid upon each other, heated, and hammered into the form of part of a plate; and the process being repeated by like additions at the end of this, the requisite length of plate is gradually produced. In other cases the hammered plate is more simply produced by successively welding together lumps or masses of scrap iron, to the required length. It has been objected to such, and in a degree to all hammered thick plates, that the iron under this mode of working becomes hard and brittle, and must lack a continuous and uniform tenacity. To this it has been replied that in properly made hammered plates, though somewhat hardened, the iron docs not lose its fibrous and tough character, that by the requisite annealing, as observations on drilling and bending the plates and experiments upon targets show, the toughness of the iron is preserved and perhaps improved by the working; while the solidity and freedom from blisters or other faults in the incorporation of the parts are greater with the hammered plates.

Messrs. Brown & Co., of Sheffield, among others, advocate and practise the making of the plates by rolling. The dimensions usually required for the frigates now building in England are—length 15-18 ft., width 2 ft. 6 in. to 8 ft. 10 in., thickness 4 ½  in. The weight of on unfinished plate of usual size, as it comes from the rolls, is 80-140 cwt.; a few inches being cut from the sides and ends, the weight of the finished plate ranges from 60 to 110 cwt. In the making of a 5-ton plate, bars of Page 617 iron are first rolled to 12 inches broad by 1 thick and sheared to 30 inches length; 5 of these are piled and rolled down to a rough slab; two such slabs are then welded and rolled down to a plate 1| inches thick, which is sheared to 4 ft. square. Four such plates are then piled and rolled down to one of 2£ inches thickness, and 8 feet by 4; and, lastly, 4 of these plates are piled and rolled to form the entire plate. There are thus welded together, during their successive reduction in thickness, 160 thicknesses of plate. That blisters and imperfection of welding and of cohesion should occur in a plate so produced is inevitable, especially, on account of the difficulty of bringing so large a mass to a perfect welding heat throughout, during the final operation of rolling into one the 4 large plates, each of 2j in. thickness; and this want of perfect incorporation is held to be a source of weakness, by reducing the thick plate, in some degree, to the condition of laminated armor composed of plates extremely thin. Some plates recently made in this way, however, and of 5 inches thickness, have been proved, by experiments upon them at Shoeburyness, to possess a very satisfactory degree of tenacity and strength.

The subject of the methods adopted in fastening the armor to the wooden or iron sides of the vessel, by means of bolts, screws, &c, is one of too much detail to be interesting to others than the ship-builder or artisan; and, besides, it is probably not in all cases fully made known. It is still a matter of much difficulty to fasten any armor securely enough to the actual hull of an iron ship through a considerable thickness of wood backing; and, again, to fasten thick plates strongly to either an iron or wooden hull without, at the same time, weakening the plate by the number or size of the bolt-holes. The attempts to render thick plates in effect continuous by tonguing and grooving appear to have been abandoned on account of their expense, as well as of the weakness of the union thus made. Different patents have lately been taken out, however, for modes of fastening, partially or wholly, of the character here referred to, and both in this country and in England; as well as others for providing the plates with flanges within, through which only the bolts requisite for fastening are to be passed. Plates may be fastened, to some extent, by bolts made to protrude only from the back, or by holding them between angle-irons; and it is believed that they may yet be strengthened at the joints by welding, in the manner lately employed with boiler joints, by moving along the part light furnaces, from which a jet of flame is blown upon it, and following up closely with hammers. In some of the target experiments, in which the thick armor plates were fastened by means of screw bolts, screwed np from the inside, the bolts broke off short at the nuts whenever the target was struck by heavy shot. This mode of fastening is to some extent adopted in the Monitor turrets, and for the plates of the New Ironsides, in the former of which some bolts have been broken, in the way named. An easy remedy appears to offer itself in screwing up the bolts less tightly.

The Aspects of the Armor Question meanwhile Changing.—The aim of the preceding part of this article has been to show the more important steps by which the plan of armoring ships became gradually matured, and to present in brief the several modes of armoring that have been actually and in rapid succession resorted to up to the beginning of the year 1863. Still, the armor actually adopted constitutes only one side of the question, and this, in fact, the secondary one. For, so long as the power of ordnance can be yet further increased, the demand for increased capability of resistance on the part of the armor of ships grows in the same ratio; and just so long the issue between the two remains undecided. The struggle is, on one side, for positively irresistible artillery; on the other for absolutely invulnerable ships: will either of the two finally and completely distance its antagonist? and if so, which one? or will the two come ultimately again to a tolerable balance of chances, such as, some 50 years since, existed between wooden ships and broadsides of the largest round shot then in use? and, if this is to be the result, through what steps is it to be reached?

It is a well-known fact that while, for the past two years, iron-armored vessels of all dimensions, and in great numbers, have been hurriedly building on both sides of the Atlantic, during this very period, and also on both sides, the caliber and firing charge of cannon have been undergoing a marked increase, and which, moreover, promises still to continue. Already shot and shell are safely and regularly thrown, which have powers of crushing and of penetration such as were not at all contemplated in the estimates of requisite strength that dictated the armor of La Gloire, the Warrior, the ordinary Monitors, the Ironsides, and their counterparts. The present phase of the armor question cannot be understood without a fair idea of the most recent advance in the capacities of heavy ordnance, and of the execution done by the projectiles thrown by it. While upon these points theoretical views must, still, to a certain extent, be accepted, much information may be drawn from the set experiments made in the way of firing upon targets; and, for the latter source, reliance must, as yet, chiefly be placed upon the English experiments, as the only ones very fully published. Some principles relating to the subjects of ordnance and projectiles must, of course, here be introduced as preliminaries.

Destructive Power of Projectiles.—The momentum, or quantity of motion, in a moving projectile is proportional to the product of its weight into its velocity; that is, momentum varies as "W X V. This is the measure of the Page 618 capacity the projectile has, if instantaneously stopped by some other body in any part of its flight, to put that other body in motion. Consequently, supposing a cannon ball in no degree to penetrate armor plating against which it is fired, but to be instantly and totally arrested at the surface, this momentum is also the measure of the shock or concussion the ball will give to the armor. The ball, having its motion extinguished, either the ship as a whole or the part struck must be proportionally moved; and, remembering that the most rigid sides of iron and wood will, still, bend, and may fracture, while it is the nature of inertia to prevent the communication of the motion, instantaneously, to the whole ship, it follows that the part struck, for a greater or less area, and to a greater or less extent, according to the conditions of the case, will move from before the projectile which it arrests. If this yielding be under a blow sufficiently great, the effect will be permanently to bend the plate, or to fracture it, perhaps to drive it into the wood backing, and to start or crush the latter. In this way the plates may be fractured, shattered or loosened, the bolts driven in, or the structure of the ship, at the part, racked or strained, and perhaps a leak produced. Now, it is important to remember (a point too often overlooked) that all these effects, per se, are due to, and measured simply by, momentum, and, hence, increased directly and simply by increasing the product of weight and velocity (not of weight and the square of velocity). Thus, if the two balls be of similar form, and could act by momentum alone, then, at short range, Sir Win. Armstrong's 110-pounder, fired with 14 lbs. of powder, and with an initial velocity of 1,210 It. per second, should have, to the common 68-pounder, fired with 16 lbs. of powder, at an initial velocity of 1,580 ft. per second, a damaging effect in the ratio of 110 X 1,210 to 68 X 1,580; or, nearly as 13 :11.

But precisely to the extent that the material and structure of the ship's side combine to give rigidity and immobility to the part struck, so that, while the gradual operation of inertia' will not allow the whole ship to recede, these qualities refuse to allow the part to yield through any considerable extent so as to be crushed in or fractured and recoil, it will then be true that one or both of two other results must follow, namely: the projectile must expend the quantity of force stored up in it in the way of compressing, flattening, or crushing its own mass, in the first case, perhaps rebounding, either whole or fractured, or else it must expend the same force in the way of overcoming the cohesion and resistance of the materials it strikes, and pushing or cutting its way into or through them. But this quantity of force or work stored in the moving ball is proportional to the product of its weight into the square of its velocity; that is, the work varies as W X V. It is already evident, then, that the execution of a ball or shell in the way of punching or penetrating the armor, and generally the Bides, of a ship, must also be in this ratio: it increases, so far as the mere force is concerned, as weight and square of velocity. Supposing, then, their entire energy to be expended in the way of penetration, the projectiles above named would be capable of damaging effect in the ratio of 110 X 1,210' to 68 X 1,580'; or, nearly as 16:17; so that here, allowing for the Armstrong projectile the highest initial velocity claimed for it, the advantage is still on the side of the 68-pounder, with larger firing charge and higher velocity. The weights of projectiles of like form being, in general, as the products of their diameters and densities, it may be correctly said, also, that their punching or penetrative capacity will be as the products of the three factors, diameter, density, and velocity square.

Thus, projectiles can have two sorts of effect upon obstacles, say the armor or sides of a ship, namely, that of pushing or crushing away the part before them until their motion is consumed in imparting an equal motion; or, that of overcoming their own cohesion or that of the part struck; in the latter case driving or cutting into the part until the work stored up in them is in this way expended. But since, generally, under the instantaneous blow of a projectile the armor and side of the ship, in degree, both yield and refuse to yield, it follows that, in actual cases, the two kinds of effect will usually be mixed, though one or the other may predominate. It would appear, however, to follow that, other things equal, very large and heavy projectiles, thrown at a lower velocity, should be relatively more effective in the way of fracturing or shattering armor, and straining the general structure of the part, while shot or shell of less weight, from guns bearing a heavy charge of powder, and giving a high initial velocity, should be more effective in the way of penetrating the armor and sides, as where the object may be to cause a leak or to carry shells into the interior. This distinction, questioned by some authorities, and not always clearly drawn, appears, still, to be that more generally held as practically correct.

Sir Wm. Armstrong concludes that it is not by piercing small clean-cut holes with steel shot, that a ship is to be disabled or destroyed, but by knocking large ragged holes in the side, and rendering the interior untenable from splinters. Stating the case, however, in the most general way, it appears that the greatest amount of destructive effect will be produced by the guns which can give to the heaviest projectiles the greatest velocity; and this amounts to saying, in other words, those which with a given caliber and weight of projectile admit of being fired with the heaviest charge of powder. In spite of some assertions to the contrary, the opinion is now gaining ground that the superior execution of the new wrought-iron, hooped, or otherwise strengthened forms of ordnance, over Page 619 the usual cast-iron guns, is especially due to the increased charge—35 to 60 pounds, or more, of powder—of which their greater tenacity and strength admit. So far as smooth-bore guns admit of heavier charges than rifled, the former have also the advantage in this respect; but there are important differences in the behavior during flight of the two kinds of projectiles, that must also be considered. At short ranges, say, under 400-600 yards, the round shot of the 6mooth-bore gun still moves with somewhat nearly its initial velocity ; but this it is rapidly losing, owing to the greater resistance it encounters from the air; and a little farther on it is outstripped by the rifled projectile, which at long ranges is thus the more effective. Admiral Dahlgren says, "The rifle shot has greater penetration than the round, but much less concussive power. ... If, in battering an ironclad, penetration only shall be the paramount consideration, and other effects merely incidental, the rifle cannon must be selected. But if the concussion and shattering of the plate and its backing be preferred, with such penetration as might be consequent thereon, then the heavy, swift, round projectile will supply the blow best adapted to such work. So long as the present mode of plating continues, there can be little doubt that it will be most effectively attacked by cracking and bending the iron, starting the bolts, stripping off the armor, and breaking away large portions of the wooden structure within." In respect to the form of the ends of shot, Prof. Fairbairn's experiments appear to prove that the penetrative power and effect of round-ended is twice as great as that of flat-ended projectiles.

The material of the shot has also an important bearing upon the nature of its effects. In striking armor or other rigid obstacle, hardened steel shot undergo less compression than any others, and their great tenacity renders them but little liable to fracture; hence, the work of which they are capable is, in higher degree than with other sorts, expended upon the opposing body. For round-ended shot, Prof. Fairbairn has found by experiments in punching plates, that when these are of steel, the dynamic resistance or work of which they are capable is more than three times that of like shot of cast iron. He concludes (in a paper read before the Brit. Assoc., 1862,) that the conditions apparently desirable in projectiles, in order that the greatest amount of work may be expended upon the armor plate, are: 1. Very high statical resistance to rupture by compression. In this respect, wrought iron and steel are both superior to cast iron. The statical resistance of steel is more than 8 times, and that of wrought iron more than twice, that of cast iron. Lead is inferior to all the other materials .named. 2. Resistance to change of form under great pressure. In this, also, hardened steel is superior to wrought iron, and cast iron inferior to both these. Finally, the shot which would effect the greatest damage to a plate would be one of adamant, incapable of change of form. Such a shot would yield up the whole of its tit viva to the plate. And experiments prove that the projectiles that approach nearest to this condition are the most effective. The much greater cost of steel shot has hitherto stood in the way of their adoption ; but M. Bessemer appears to have assured Fairbairn that he could produce steel shot at little more than the cost of those of cast iron. Dahlgren asserts that the actual damaging effect of cast-iron is greater than that of wrought-iron shot, in that, while the latter is merely flattened or crushed by impact, and tends then to lodge in the plating, the former, though it breaks, is more apt to pass completely through, making a larger hole, and badly cracking the plate.

In this country, guns for throwing very heavy shot—450-476 lbs. solid"—are in successful use; and one at least for throwing a 10001b. ball is already constructed and in readiness. But the most recent change in the direction of efficiency of shot, appears to be in the adoption of the plan, which had already come into favor in England, of larger charges of powder. The maximum charge, up to this time, has been 35 lbs. of powder. The Government, it is stated, has now ordered cannon, preparations for fabricating which are already in progress, which will bear the explosion of 60, and possibly of 70 lbs. of powder; and it is believed that the 450-lb. shot thrown with such a charge, will prove the most destructive missile thus far ever employed. Admiral Dahlgren, also, in his recent report, states as the result of repeated and severe tests of their capacity in this particular, that the 9inch and 11-inch cast-iron guns, until recently the largest in use, bear continued firing with charges much greater than those for which they were intended; the 9-inch one half greater, and the 11-inch with double the original weight of powder.

Resistance of Iron Plates.—The law admitted to hold generally true in respect to the resistance of plates of any given kind of iron to punching or fracture, is, that such resistance is directly proportional to the sheared or fractured area—the total length and breadth of metal, throughout which the cohesion of the particles is overcome,—and hence, that it is as the depth and diameter of a hole cut in the plate, or as the total length and depth of the fracture produced in it.

The question as to the relation the strength and resistance of a single homogeneous plate bear to its thickness, appears not yet to be decided. Experiments early made at Manchester appeared to show that the resistance varies directly and simply as the thickness, so that a plate twice as thick as another has only twice its power of resisting impact. During the last year, however, at Shoeburyness, a target of 5-8 inch boiler plates, with a l ½ -inch plate in front, the whole held together by alternate rivets and screws 8 inches apart, and having a thickness Page 620 of 8 inches, was completely penetrated by the8-inch 68-pdr. smooth-bore gun and the 100-pdr. rifle, at 200 yds., though at like range these guns have not greatly injured the best 4 ½ -inch solid plates; and a 10-inch target similarly constructed was much bulged and broken at the back by the same guns. From these and other data, Fairbairn deduces a conclusion in common with that now generally held in England and France—and made in those countries the leading argument in favor of armoring with single thick plates—namely, that up to a certain limit, and which lies beyond the thickness of any plates yet adopted, the resistance of the plate to shot increases very nearly as the square of the thickness; so that with thicknesses of 1, 2,8, etc., the capacities of resistance are as, 1, 4, 9, etc.; and that a single 4-inch plate has practically about twice the strength of two 2-inch plates laid together, though the latter give the same total depth of metal. In the experiments of Mr. Stevens in 1854, however, a 10-inch 125-pdr. round shot, with 10 lbs. of powder, and having about the same penetrating power with either of those above named, only slightly indented and did not break a 65-inch target composed of plates of similar thickness to those made use of in the English experiments. It is stated that the experiments, individual and official, on the subject in this country concur in showing oven a superior resistance in laminated armor. The comparatively smaller firing charge, and lower velocity of ball which have here been hitherto the rule, may serve in part to explain away the value of these results. In explanation of the assumed superior resistance of single thick plates—though the fact makes against them when penetration actually occurs—it has been urged that in punching such a plate with a projectile, the hole made is conical, about the size of the ball in front, and much larger at back, while the hole made through laminated armor is cylindrical; so that, in the former the sheared or fractured area must be much greater. Besides the area of fracture, however, and the absolute thickness of single or partial plates, many other circumstances must enter to decide in a given case the relative capacities of the ball and the armor. Among these are: differences in the qualities of the metal of the ball and of the armor, as in case of the best hardened steel shot striking armor which has either too great brittleness or too great softness; the presence or absence of uniform cohesion and strength throughout the thickness of each single or partial plate, depending on the manner in which it has been manufactured; the necessity of joints and bolts or rivets in the armor—almost always elements of weakness at the points where they occur; and the extent to which the mode of applying and fastening the plates is made to prevent or compensate such weakness. The latest conclusions still appear to be to the effect that, for the most effective sort of plating, the three qualities requisite are; 1, that the iron shall not be of a crystalline texture; 2, that it shall possess considerable ductility are the greatest possible tenacity; 3, that, to these ends, it shall be a very fibrous iron. To these qualities it will probably have to be added that, fourthly, in order to effectual resistance to the almost unfracturable shot of metal having the utmost tenacity and hardness, the possession also on the part of the plate of the utmost hardness compatible with the three qualities above named, is indispensable. Beside the use of Franklinite, presently to be referred to, it has been suggested that possibly a very low Bessemer steel, or iron, as likely to supply all the needful conditions, may yet be cheaply adapted to the making of armor plates.

Mr. A. L. Holley, after remarking that our information in respect to the relative strength of single and laminated armor is still too incomplete to warrant a conclusion, adds: "It is probable that the heavy English machinery produces better-worked thick plates than have been tested in America, and that American iron, which is well worked in the thin plate used for laminated armor, is better than English iron; while the comparatively high velocities of shot used in England are more trying to thin plates, and the comparatively heavy shot in America prove most destructive to solid plates. So that there is as yet no common ground of comparison [between the results obtained in the practice of the two countries]." In respect to joints and fastening, Fairbairn was led by tests made with a view to this particular subject, to the result that, taking the cohesive strength of a given plate at 100, the strength of an ordinary double-riveted joint is about 70, and that of a single-riveted joint not more than 56.

It appears very recently to have occurred to the English naval authorities that the bending of the thick iron plates to fit the ship's sides, as has so far been practised in case of all or nearly all their armored vessels, must render, the plates so bent more vulnerable. Very few of the American armored vessels have been constructed with bent plates; among such are at least the Roanoke and the Onondaga. It would seem that the greatest strength, in this respect, would be secured by forging the plates as nearly to the required shape as possible, and then fitting the sides or backing to the plates, rather than these to the surface they rest won.

The Recent Experiments with Modem Heavy Ordnance.—In October, 1861, a target 20 feet long by 10 feet wide, and representing the side of the Warrior—4 ½ inches of solid iron on 18 inches of teak backing, with an inner lining of ½ -inch wrought iron—was fired on at 200 yards' distance, at Shoeburyness, during the principal part of two days, with solid 68-pounders, 110-pounders, and 200-pounders, both singly, and also in salvos of 8, 4, and 6 guns at a time, concentrated on white spots painted on the supposedly weaker parts of the target. The missiles simply rebounded, or broke and flew Page 621 off in fragments; and though they battered the plates and heated them in parts almost red hot, yet none of them passed through, nor, until the final salvo of 6 100-lb. balls, fired with 16 lbs. of powder each, and aimed on a single spot to one side, did they even fracture the outer plating: the effect of this last fire, however, was to make a gap in the outer plate 15 inches long and its whole depth, loosening some of the bolts, but not really disturbing the backing or inner plate. The conclusion for the time was, that the Warrior style of armor was practically invulnerable to the ordnance at the time in use.

But during the whole course of the experiments at Shoeburyness, it was observed that the smooth-bore 68-pdrs., fired with more powder, left their mark in deeper dints in the plate than did the Armstrong rifled 110-pdrs.—a fact the cause of which has been shown in the section on the Power of Projectiles. This led to or strengthened a conviction in the minds of those interested in the making of ordnance, that large wrought-iron guns, strong enough to bear heavy firing charges, would at close range penetrate the armor which came so triumphantly out of the previous tests. Sir Wm. Armstrong accordingly had a gun fabricated for elongated 300-lb. shot, its bore 10 inches and greatest diameter 38 inches, and which, not having been rifled, was fired (April 8, 1862) with a 156-lb. round shot and 40 lbs. of powder, against the target above described, or a similar one: the first shot crushed the outer plate at the point struck into "crumbs" of metal, splintered and mashed the teak backing, and badly sprung the inner plate; and the second, striking near, aggravated the damage and its extent. The charge was then increased to 50 lbs., and the third and fourth shots each went, at different points, completely through the outer plate, backing, and lining, burying themselves in the timbers supporting the target. A change of opinion in reference to the practical invulnerability of the Warrior armor, at least for a square hit at short range, of course set in; and although for a time it was urged by some that the actual damage to the target had been overstated, and in spite of the fact, that after some 160 discharges the Armstrong gun burst, showing that the charges used were too much for the metal and construction, the more decisive experiments, soon afterward made, completed the overthrow of the confidence previously entertained on the side of armor defence.

The experiments in firing solid shot and shell upon targets were renewed in August, 1862; and upon an occasion on which members of a select committee of the Government on iron plates and ordnance were present, the new Horsfall wrought-iron smooth-bore gun, caliber 13 inches, weight 22 tons, and carrying a 286 lb. solid ball, as well as other pieces, was tried. The standard Warrior style of target being used, range 200 yds., and charge 75 lbs. of powder, the first shot smashed through the entire target, striking out a huge hole more than 2 ft. in diameter, cracking the surrounding iron in all directions, and unfitting the target for further experiments. The gun appeared to be in no way strained or injured by the fire.

In the experiments previous to this time, the shells fired against armor of moderate thickness had been broken; and it had been held that vessels covered with 2J-inch plates were shell-proof. A Whitworth rifled breechloading 12-pounder field gun of 4-inch bore was on this occasion loaded first with a flat fronted solid steel shot, and fired at 100 yds. upon plates of 2 and 2 1/2  inches: in both cases the shot cut their way clear through the plates. The same gun was then loaded with a flat fronted steel shell, containing 6 oz. of powder, and fired with a charge of 80 oz.: no fuze was employed, but, as expected, the concussion ignited the bursting charge; one such shell passed through a 2-inch plate and 12-inch oak backing, another pierced the plate and burst in the backing, shattering it to pieces. A Whitworth 70-pdr. naval gun was then tried against a target of 4-inch plating on 9 inches of oak, attached to another frame of four inches of oak, lined finally with a 2-inch iron plate, the space between the two frames being 30 inches. A 70-lb. flat-fronted steel shell, fired with 12 lbs. of powder, at 200 yds., was driven clean through the first plate and backing, reached and fractured the 2-inch plate, and then burst, shattering the target. Prof. Fairbairn concludes that, against such weapons as those employed in these experiments, no American gun-boat [query, iron-clad vessel ] is proof; but that, with Whitworth's hardened steel shells, such vessels could be destroyed at 1,500 -2,000 yards. It was observed in these experiments that the Whitworth flat-fronted steel projectiles cut clean holes through the outer plates, without fracturing them as did the ball from the Horsfall gun. It was believed by those present at the trials, that the latter would have gone through a plate 6 inches in thickness.

September 25, 1862, experiments were made with the same Horsfall gun, and an Armstrong 120-pdr., rifled on Whitworth's plan, the range now being 800 yards for the former (13-inch) gun, and 600 yards for the latter (7inch). The target was 21 feet long, 15 feet high, of the Warrior pattern, already given, and strengthened within by a framing of massive angle irons, set 18 inches apart. The Horsfall gun was fired 14 times with solid shot of 275 lbs., and a 75-lb. charge, at least two of the shot striking. One, a ricochet, bounded from 40 yards in front, smashed through the armor, making a great hole, shattering the teak and fracturing the lining, but not passing through; another, striking the upper corner of the target, made a huge fracture, breaking out several great pieces from the outer plate. The Whitworth rifle, with a firing charge of 23 lbs., sent a solid hexagonal Page 622 flat-fronted shot, 13 ½  inches long, weight 130 lbs., through the armor into the wood, shattering one of the angle irons, but not going through. With the same gun, a shell of "homogeneous metal" (low cast steel), 17 inches in length, holding 3J lbs. of powder, weighing 130 lbs., and tired with a 25-lb. charge, was sent clean through the 4-1/2 -inch armor plate and the wood backing, exploding as it struck the inner plate, and tearing the latter into fragments. The solid shot and shell from this gun made clean 8-inch holes through the armor; and their velocity at the moment of impact was ascertained to be 1,284 ft. per second. Thus, the standard English system of armor was proved to be completely vulnerable oven to shells; but, on the other hand, the result appeared to be due to the high firing charge and velocity secured by the Horsfall and Whitworth guns, and to the use with the latter of the hardened steel shot and shell; so that the English authorities consoled themselves with the conclusion that, in comparison, the French navy rifle guns, and the American cast-iron Dahlgren guns are "useless against iron sides." It appears that, still more recently, the A Whitworth rifle, last referred to, has thrown a 150-lb. shell, holding 5 lbs. bursting charge, and fired with 27 lbs. of powder, completely through a 5 ½ -inch armor plate and 9 inches of backing, the shell exploding in the space beyond, representing the hold of the ship!

In respect to recent experiments in the United States, as already implied, although these have been now for a long time in progress at Washington, as well as, perhaps, elsewhere, and, it appears, on no limited scale, very little connected with the results has yet been made public. It is said that the hollow 375-lb. shot of the 15-inch guns, their walls 3 inches in thickness, thrown against l0 ½ -inch laminated armor, backed with 18 inches of oak, were broken without doing serious damage to the armor. Admiral Dahlgren speaks of a new class of gun—caliber not positively given, though probably 15 inches—which, at 200 yards, has sent its shot, with ease, through 5 ¼  inches of iron plates and 18 inches of oak backing.

Practical Qualifications as to the Relative Efficiency of Guns and Armor.—Even, however, the facts that the most powerful ordnance has sufficed to pierce and demolish fixed targets, under a fair fire on land, do not prove the actual (similar) armor of ships useless; and many qualifications of the results above found in reference to the resistance of plates and the power of projectiles must, in practice, come in on both sides—so many, in fact, that the actual trial of the two in naval engagements must finally decide these questions, and may decide them quite differently from any present anticipations. Prof. Fairbairn considers that the victory is now in favor of the guns, and that it may be difficult to construct ships of sufficient power to prevent their destruction by entrance of shells. Again, the destructive effect of ordnance generally is greatest at short range, and on account of the limited number of guns usual in the new styles of armament, and the known resisting power of an antagonist's sides, as well as the difficulties of aiming at sea at a distant moving object, iron-clad warfare will probably be carried on as a rule at close quarters. Still there are many circumstances which will be availed of on each side to delay or avert a conclusive blow, until its own guns can be brought into play. Thus, in favor of the armor and ship (defence), there are the uncertainty of securing a square hit, even on vertical sides; the danger with large charges of bursting of the antagonist's guns, an accident but too much favored by the new charges of i to £ the weight of the ball; with certain styles of iron-clad, the limited number of the guns, and in proportion as these are of large size and heavy firing charge, the necessity of longer intervals—with 15-inch guns, not less than from 8 to 8 minutes—between the discharges; the relatively small chance, where a partial damage has been inflicted, of increasing or completing it by another shot upon the same point; and so on. It would for the present appear that the 20-inch 1,000-pdr. guns must be confined to use in forts, and from which their steady aim would enable them to tell with terrible effect on vessels even at a distance of 1,000 yds. or more; so that while they are obviously desirable for harbor defence, they are likely at the same time to be in the main or wholly excluded from naval conflicts.

On the other hand, in favor of the guns (attack), are found such facts as, that the practical thickness of armor and backing must always be confined within a small limit; that heavy armor on a ship's sides, more especially when far removed from the frame and proper walls of the hull by intervening thick wood backing, continually exerts a strain tending to break down the sides, and thus in effect cooperates with the racking blows of heavy projectiles; that an enemy's portholes are always exposed to the entrance of the most damaging missiles at the moment of being opened for firing; that the concentration, in partially protected vessels, of armor over casemates and at the water line, necessarily leaves some parts vulnerable, &c.; while to all these circumstances another arising from an entirely different source must be added; namely, that the targets used in the experiments made on land have unquestionably possessed a greater strength and resisting capacity (though this is perhaps less true of laminated armor), than is likely to be found in any section of an actually armored ship's side, which they are intended to represent.

The Question of Inclined or of Vertical Armor.—The principle of inclining the armor from the vertical, so as to favor the glancing of Page 623 shot, and save the plates from receiving the full force of the blow, appears to have been first proposed by Mr. Josiah Jones, of Liverpool. Among the experiments made to test the value of this plan, were those in England, in 1861, in which an 8 ½ -inch solid plate fixed at an angle of 45° was more injured by elongated 100-lb. shot, than a 4 1/2 -inch solid plate in a vertical position, the two plates having the same backing and equal weights of metal in the same vertical height. In fact, the Iron Plate Committee have recently reported that with any practicable inclination from the upright—as much as 62°—it takes the same weight of iron to cover effectually with armor a certain length and height of side, whether this be inclined or upright. This is but another mode of expressing the conclusion arrived at by Mr. Stevens in this country, that a given thickness of iron measured on the line of fire, whether the plate be fixed in a vertical or an inclined position, offers about equal resistance to the average shot striking it. These general statements must, however, be to some extent qualified, both for the form of projectile and sort of gun, on one hand, and for the relative hardness of the armor surface, on the other. Elongated projectiles thrown from smooth-bore guns are notoriously uncertain of effect in a first oblique impact, and of direction after being from any cause once "ended over" or glanced. "With projectiles of such form, rifling appears indispensable, in order to give persistency in direction of flight, and to keep them on end while cutting into armor. And in such case, especially if the shot be hardened and flat fronted, it is not glanced except by armor set at an angle with the horizon so small as to be impracticable, in view of its forbidding the proper accommodation and working of the guns, and rendering the hull deficient in stability and bearing; while, further, if the shot are glanced, and. often in that case in fragments, they must prove so destructive to objects on deck as to render masts, rigging, and sails unavailable. Round shot, indeed, are likely to be glanced by armor set at an angle of about 40° or more with the vertical; and in experiments on the subject in this country, a 61-inch laminated target, vertical, was by a 128-lb. spherical shot indented about 4 times as deeply as 6-inch plate, also laminated, fixed at an angle of 27°. Besides the disadvantages of inclined armor already named, are those of its greater expensiveness, the waste of room it occasions, and the fact that to a more direct fire from elevated guns, as those of shore batteries, its less actual thickness renders it quite vulnerable. In fact, in the United States comparatively few armored ships have been constructed with inclined armor and in England the principle is regarded as abandoned. Since, on the part of the armor, a surface at once highly hard and tough must increase the tendency to glance shot, the use of the Franklinite iron for surface plating may be found to render a practicable inclination of greater value as a means of protection; and experiments with a view to this end are said to be in progress.

In the Exhibition of 1862, Mr. C. J. Richardson exhibited drawings of a modification of the inclined principle for the sides of ships, he proposes to apply the armor in the form of projecting conical shields, each shield having slightly curved projecting lips or bases; the forms being such as he believes will cause shot striking to be deflected in a direction back toward that from which they came. He makes the portholes either circular or oval, and continues the circular lip round them, so that shot glancing over the surface of the shield may be deflected from this also. Mr. J. W. Couchman, in a model of a floating battery, combined with vertical ports the sloping side between ports, as attic windows are formed in a sloping roof. The necessity of rendering the sides and roofs also of these ports shot-proof, would probably make the proposed armor enormously heavy.

The Question of Kind of Armor, and of Backing.—So far as the data upon which must be decided the question between the claims of laminated and of solid armor have yet been determined, those data have, it is believed, been in the main embodied in the foregoing parts of this article, and particularly in the section on Resistance of Iron Plates. Each method of plating has its own advantages, and its own defects; and while it is certain that the question of the relative value and desirableness of the two systems has not been decided either way, the final result may be in finding each of them the more eligible for particular sorts of vessel or kinds of service. Certain well-conducted experiments would seem to prove at least that, with the same thickness of iron, the solid armor throws off and keeps out a shot which may deeply indent or pass through the laminated. This might be quite conclusive, if penetration were alone the question; but such is by no means the case. "While Admiral Dahlgren gives prominence to the fact that a very thick solid plate can scarcely be made equal in texture to the thinner ones, and remarks that, in every instance in which he has seen a solid plate pierced by shot, a separation of the metal at the welds has shown the imperfection of the union there formed, Mr. Holley regards the experiments as showing so great a difference, in simple and absolute resistance to shot, in favor of the solid iron, as to leave a large margin for possible defects in the' quality of the latter. It appears quite certain that fracture is more likely to result in solid than in laminated armor, since in the latter the separate plates are more capable of yielding in virtue of their elasticity; and that, when caused, it is also more serious in the former. All thick plates are in proportion much more weakened by the necessary large bolt-holes through them than, owing to its mode of application, arc the plates of laminated armor; Page 624 and with the solid plates, as their thickness is increased, this source of weakness will be aggravated in a degree in which it is not with armor of many thin plates. Thick plates impart no strength to the ship, nor do they help to strengthen each other, but in fact hang separately as so many loads on the ship's sides, constituting again by their weight a source of strain and weakness. Thus, the Duke of Somerset, in the House of Lords, in the early part of 1862, admitted, and the statement holds equally true of all English armored ships built up to this time, "We have not yet constructed a vessel in which the iron plating adds to or assists in constituting the strength of the vessel." "A series of thin plates," however, as Mr. Holley remarks, "breaking joints and bolted through the backing, not only fasten' each other, but are in effect a continuous girder;" and in this way, they not only afford support to each other, but strengthen the entire hull at the same time. Meanwhile, laminated armor is both the cheaper and the more easily put on. On the side of solid plates, it has been urged that if the resistance practically does increase as the square of thickness, and 4 and 5-inch plates are found to tax severely the powers of the best ordnance, then in plates of 8 inches thickness is probably to be found a positive protection against the most powerful guns that can be constructed. Supposing this could with such plates be the result, the facts already presented appear to throw doubts, if not upon the feasibility of constructing them of good quality throughout, at least on that of securely and satisfactorily applying them.

In respect to the use or disuse of a wood backing for the plates, it may be stated that while English opinion and practice decidedly favor the armoring only of iron ships—and this, in spite of the recent efforts of the Admiralty to get the surplus wood in the shipyards used up in a certain number of wooden hulls,—there are those interested in the subject in that country, who argue in favor of armoring with iron on iron, dispensing with the intermediate wood. Among the advocates of this plan has been Prof. Fairbairn, who urged that while a wood backing by its elasticity and yielding soften od the blow of a projectile, this was done at the expense of the plate, since the latter would be more deflected and driven into the wood. But in all the firing upon the laminated armor of the Monitors which has yet taken place, no such result of a broad area of the plating being permanently bent and compressed into the backing has occurred. Fairbairn admits, however, that with iron on iron there is greater risk that the result of two or more heavy shot or of a well-concentrated fire might be not only to penetrate the plates, but also to break the ribs of the ship; and from results of the very latest experiments with the 300-pounder gun, he concludes that some softer and more compressible substance than iron between the armor and sides is necessary, in order to deaden the blow; so that the wood backing cannot be dispensed with. This action in the way of distributing and softening the blow upon the hull and ribs of the vessel, as well as upon the armor, appears to be the true function of the wood backing, so that while it adds little to the real strength of armor, it adds greatly to the protection of the ship, and may be considered as generally indispensable. And again, though such backing is subject to the disadvantage of being fired by shells, it becomes a special and important protection of the ship's crew and force, by arresting or preventing the discharges of iron splinters, otherwise so likely to be driven into the interior.

Extent of Armor, and Plans of Armored Vessels.—As American practice in constructing armored vessels has thus far favored moderate or comparatively small dimensions, so it has tended most strongly to the plan of complete and nearly uniform protection of the entire hull, to a depth below which penetration becomes very unlikely. The French and English practice, directed chiefly to sea-going vessels, and hence of generally large dimensions, has been divided, but in good degree, it would appear, driven—through the desire of preserving speed— to the plans of partial armoring, as previously described. With ships of large size, it appears quite evident that—and especially as against the most recent styles of guns and projectiles— armor from stem to stern, and of a thickness to be invulnerable, is a thing utterly impracticable, at least without such a weight of metal as to sacrifice all desirable manageableness and speed. Besides, it is argued in England that, while the complete mailing of the Royal Sovereign, Prince Albert, and others, as intended for coast defence is well enough, vessels mailed on this plan could not properly lift their loaded ends in a heavy sea, so that these must in such case continually be submerged by the waves. Consequently, for large sea-going vessels, a sufficiently armored casemate, or turrets, amidships, with a broad belt of armor at the water line, a shot-proof deck being formed at the upper level of this armor belt or at water line, the hull being as much as practicable divided into compartments severally water-tight, and with pumping engines and pumps of good capacity within the protected space—such, keeping in view sea-going qualities, celerity of turning, and speed, appears to be in brief the general plan indispensable to securing at once any sufficient degree of practical invulnerability and fair chances of keeping afloat. Since there must somewhere be a shot-proof deck, the placing of this near water line does not increase the weight of the hull, though it may have some effect on its stability; but it saves a considerable weight of metal from the unarmored parts, a portion of which can well be used to strengthen the armor where applied. Again, it has been proposed, with hulls of the ordinary height out of water, to save weight Page 625 and increase the strength of armor by plating more heavily at the water-line belt, and again at the height of the battery, with a lower shot-proof deck, as before, and shot-proof passages leading from the lower protected space to that of the battery or gun deck.

Large dimensions of hull, by increasing the carrying power of the ship in a more rapid ratio than the resistance it meets with in motion, allow not only of heavy armor and armament, but also favor speed; so that, in a general way, such dimensions must be aimed at in sea-going ships. But an important increase, on the other hand, in a vessel's efficiency may be secured, as is aimed at in the Monitors, by dispensing, as far as practicable, with everything but a protected hull, a battery and its auxiliaries, and engines for propulsion, for the needful work of ventilating and pumping, and working the turret, if not of serving the guns; the latter, meanwhile, by .the device of the revolving turret, being reduced in number and increased in caliber and power. The settling, however, of the Montauk’s turret, under the blows of shot from Fort McAllister, and the blocking of the turrets of the Passaic and Nahant, in the attack on the forts in Charleston harbor, show that in order to secure a good degree of endurance and efficiency in actual combat, some important improvements are yet required, and, perhaps, intimate that, with small vessels of this construction, the largo armaments of line-of-battle ships will have to be replaced by the large number of turrets, and so of hulls, composing an attacking fleet. Since the attack referred to, Captain Ericsson declares that the construction of the turrets and pilothouses of the Monitors is purposely made such as to admit of the application of additional thicknesses of plating, if this (as now appears to be the fact) should be proved necessary; and he implies that all the apparent imperfections in the batteries, shown by that contest, can be readily and completely remedied.

Among the means which appear to promise a great increase in the efficiency of small batteries may be named the plan of Mr. E. A. Stevens, of "elevating and lowering, by hydraulic machinery, the turn table on which the gun carriage is fixed, so that the gun can be fired above deck, and loaded and protected, except at the moment of firing, below a shot proof structure; and especially Mr. Stevens' arrangement for loading and cooling guns rapidly by simple steam machinery;" as well as the plan of "a rotating battery, designed by Mr. Julius King, of New Jersey, in which two or more guns are loading below deck, while another in the same revolving frame, and covered by a shot-proof hood, may be trained, elevated, and fired above deck." [Holley.]

It is stated that Mr. E. A. Stevens has recently, with the proviso that the Government shall purchase it in case of success, proposed to complete his well-known battery at his own expense, and then to submit it to the severest tests known to modern navigation and gunnery, among its assumed qualities being a speed of 20 miles per hour, capability of turning in an extremely short time on its own centre, and invulnerability to shot of the most powerful known ordnance. This last quality is in a good degree to be derived from the submersion of the hull, during action, to such a depth that the lower deck shall be considerably beneath the surface of the water, the deflecting influence of which is held to afford the most efficient possible protection to the hold, with the engines and machinery, so enveloped. The bottom of this battery is of wood, and so, free from the fouling which proves, after a little time, so serious a barrier to speed with vessels having iron bottoms, unprotected.

The question of the best construction of hull for armored ships is, in fact, still by no means settled. The comparatively thin shell of a very nsual style of iron ships, perforated by rows of holes running in the direction of the ribs, is manifestly a source of weakness in reference to transverse strains; while the shell may also be crushed in by collision with ledges of rocks, or a blow from the flukes of an anchor. To remedy these defects, it has been proposed to apply a thick wooden sheathing outside the iron shell, and over this copper or brass sheathing; and, again, to introduce a double bottom, as is done in the Great Eastern, and in the new English "shield" ships; an objection to this being that the necessary allowance of space enough between the two bottoms to admit of the entrance of workmen, diminishes greatly the available room of the hold.

Experience in this country appears not to favor the armoring of old wooden vessels for the new sort of service; but whether or not the proper hull of an armored ship were better constructed of wood, appears to be still an open question. The wooden bottoms, with or without copper sheathing, have the advantage of fouling far less than those of iron. The iron surface, acted on by salt water, rusts rapidly and unevenly, and then affords a lodgement to barnacles and -seaweeds to such an extent as to unfit it for gliding easily upon the water, thus reducing the speed. Lord Palmerston declared that the 'Warrior fouled so fast that she lost a knot an hour in speed every six weeks sho was afloat; and such vessels, if the bottoms be not in some way protected from this action, require frequent docking and cleaning, and are not so suitable for long voyages. Copper sheathing oxidizes slowly and more evenly, and thus constantly dislodges the foreign bodies that would become attached to its surface. But against wooden hulls, on the other hand, it is an objection that they work more under the action of a heavy sea than does a well-constructed shell of iron; and this is by far a more serious difficulty in the case of single thick plates than in that of laminated armor. Page 626 Hence, in England, a very strong feeling, on this score, adverse to wooden hulls exists in naval circles. It is stated that the four large frigates which lately made a trial trip to Portugal returned with their plates so loosened that they required to be at once docked and repaired. Mr. McKay, favoring wooden hulls for reasons some of which have been given, asserts that, since thick oak planking of from 40 to 60 ft. in length, can be obtained in abundance in Delaware and Ohio, and nowhere else on the globe, therefore far stronger wooden vessels can be built in America than in the old world.

One very apparent result of the great innovations which are being made in the construction of ships of war is, that but little attention is paid to ornament, or even to beauty of form. This, in view of the more vitally interesting questions that are now at issue, is not surprising; and some of the armored vessels and designs for such are not a little strange and uncouth. The decoration of the head and of the stern and quarters of these vessels is wholly sacrificed; both extremities of the ship are plain, and, in some instances, scarcely to be distinguished, unless it be by some such mark as the unsightly cowl sometimes employed to protect the rudder post where it rises through the deck. If many of the new styles of vessels have any beauty whatever, it is only of the sort that springs from utility, and a utility—in this particular class of cases—which it requires a good degree of philosophy to discover.

Preserving the Bottoms of Armored Vessels. —The bottoms of wooden vessels not covered with sheathing are known to be liable to become worm-eaten; while a sheathing of iron, or an iron shell, becomes rapidly fouled. The value of copper sheathing has been above referred to, as also the method of covering iron bottoms with wood and then with copper. Against this plan it is urged that the timbers so applied give no structural strength to the ship, so that while the frame requires to be as heavy as before, the whole timber applied is so much additional expense. Brass or copper cannot be applied as a sheathing directly over an iron bottom, on account of the galvanic action and rusting of the iron that would thus be induced. Only two methods appear to remain. Of these, the first is that of sheathing with copper over iron, but with the introduction between the metals of a layer of non-conducting material, such as bitumen of Trinidad. This is the plan and material adopted by Mr. 0. W. Lancaster, the bitumen being used to separate the metals and also to cause adhesion of the copper sheathing—the latter purpose being aided by copper studs tapped at considerable intervals into the iron plates, and riveted upon the surface of the copper sheets. This plan appears to be that now most generally in favor among English shipbuilders. There are those who doubt the practicability of sufficiently insulating the metals in this way, and who rely on the second of the remaining methods, that of coating iron bottoms with some paint or composition resisting the action of salt water, and perhaps in other ways unfavorable to adhesion of barnacles and weeds. It is said that, in 1859, the British iron steamer Himalaya ran during nine months a distance of 26,000 miles, and in all climates, and that when docked on her return for repairs, the bottom was found quite smooth and free from rust. The bottom had been coated with red lead, and over this with a composition, chiefly of asphalt. Mr. James Jarvis, U. S. government inspector, in a letter written in 1853, declares that equal surfaces of wood and of iron, one set of each coated with three coats of red lead, and the other with three coats of zinc white, being placed during the summer in the water (salt) adjacent to the Gosport Navy Yard, at the end of the time the surfaces coated with the red lead were found quite covered with barnacles, and those coated with the zinc white entirely free. "While most of the paints or compositions used for the purposes under consideration afford but partial protection and require frequent renewal, the zinc white has been found, when applied to iron bottoms of steamboats in this country, to afford the most enduring and effectual means of protection; and accordingly the bottoms of the Dictator, Puritan, and some other iron-clad vessels, are to be coated with this material.

Rams.—Mr. Stevens, some ten years since, determined on introducing into his battery, in order to give it efficiency in acting as a ram, engines of full 8,000 horse-power, although 4,000 would have given the speed of ordinary war vessels. It is universally admitted that, for the purposes of securing a choice of position, ability to attack with the greatest effect and upon any desired point, and if needful to escape, as well as that of passing forts with the least risk of being struck, speed of movement and celerity of turning are qualifications not less essential in rams than is actual strength of the hull and beak with which their blows are to be inflicted. Yet, singularly enough, no steam ram or vessel furnished with the appendage of a beak is yet afloat which possesses in high degree the important requisite of speed. A strong construction is secured, but not the rapid resistless dash of movement that must overtake almost any flying foe, and make the monster the most truly effective against whatever it encounters. Possibly this fundamental defect may be remedied in the Stevens Battery, the Puritan class, and the Dunderberg, when these are brought into service. With a mass so heavy as that of the ram, since its damage is due to momentum, a slightly greater speed than that of the vessel struck, and of course, if the latter be at rest, a slow movement, may suffice to do to the enemy's sides or to the screw and stern an irreparable injury, and that without racking the structure of the ram itself. It has been urged as particularly a mistaken plan to give unusual strength to the head and bow of a ram, as Page 627 necessarily interfering with its speed and celerity of movement; and again, that since even a flower ship may keep her broadside away from the prow of the ram, two or more of these are much more likely to make a successful assault on even a single vessel than is one.

The means of giving sufficient speed to a ram, though perhaps difficult in practice, are so simple in principle as to require no further remark. The means of securing celerity of manoeuvring are, usually, found in the use of two independent screw propellers,—as, for example, one under each quarter. By backing one of these, and driving the other in the ordinary manner, the vessel may be rapidly turned on her centre or heel. Two screws have the further advantages of allowing of the application of greater power, and of furnishing still a means of propulsion, if one, and only one, should be disabled.

In a discussion following the reading by Mr. Aston of a paper on the penetration of projectiles, before the British Association for Advancement of Science, 1862, Mr. Nasmyth is reported as saying: "The steam ram was an old subject with him. A plan was proposed by him to the Admiralty, so long ago as 1846. He thought the more destructive you can make the attack on your adversary, the better. It was not right to be torturing your enemy by drilling numerous small holes in him; it was like taking a whole day to draw a tooth. His idea was to make one large hole and sink the ship at once, with the enemy. It was a question of momentum. The first practical ram was the Merrimac. but the Southerners made a mistake in giving her a sharp end: it should be blunt. Such was the original plan of the speaker, nor had he seen any reason to alter his views. The vessel must present as low an angle as possible, to turn shot; but she must also have strength in the direction of her length, and use the utmost possible amount of steam; and to meet the objection that the impact might destroy the engines, which he did not anticipate, he would place the engines on a slide, with buffer arrangements. "With such a vessel he would dash into the Warrior as into a bandbox. The plates would be crushed at once. He hoped the Admiralty would devote a thousand pounds or two to try the effect of a ram against an old hulk, the ship Trusty, and afterward upon the "Warrior herself."

Coast and Harbor Defences.—To the familiar modes of defence of coasts and harbors, by means of forts, shore batteries, and ordinary vessels of war, with the addition in case of the latter of sunken obstructions, chains, &c, the recent progress of naval warfare has added iron-clad ships, steam rams, cordons of submerged torpedoes, and the imminent prospect, if not yet the practice, of iron-armoring also the exposed faces of fortifications. The location of torpedoes and obstructions is simply the work of the engineer; but the immense importance of this new sort of sub-aqueous "outworks " to harbor fortifications, as an aid in embarrassing an enemy's attack upon the latter, and a means of preventing his running" them for the purpose of assault on the seaport they are intended to protect, is convincingly shown in the instance of the recent attack of the Monitor fleet on the Charleston forts; and the subject is one of which the importance cannot be over-estimated. "With reference to armored vessels and rams, nothing further need here be added; the points obviously to be regarded being simply that their strength, armament, and number be, if possible, sufficient for all probable emergencies.

In respect to forts and land batteries, the superior certainty of aim and efficiency of fire of guns placed in them, over those of the guns of ships, have long been well understood; and so long as the former are supplied with ordnance of the best patterns, of the largest caliber and highest firing charge, a contest of the best armored vessels with them—their walls being of good thickness and strength—would seem to remain, as heretofore with wooden ships, a matter of doubtful result. This superiority in damaging and destructive power of forts over ships is likely, as previously intimated, to reach its maximum if the former only shall be able to mount and use the new 20-inch guns throwing 1,000-lb. shot, and more especially when the endurance of the forts themselves shall be increased by iron plating. One of the 20-inch guns, manufactured at the Pittsburg foundry, is to be mounted within Fort Tompkins at the entrance to New York bay, in April, 1863. In reference to protecting the walls of forts with iron plating, it would appear that in this case some of the difficulties experienced in armoring ships will not be encountered; and that solid plating of as large dimensions and as great thickness as can be manufactured, can here be successfully applied and far more securely fastened; so that, in simple resistance to penetration, forts are likely to have the advantage over ships. The usual elevation of their guns, often of their walls, to a considerable height above the gun deck and body of the ship, give them a double advantage in another way, that they can aim a more direct plunging fire upon the deck and sides of the ship, while the balls of the latter may have of necessity to be thrown upon their walls in a more or less oblique direction.

Conclusions.—The results in the way of riddling armor targets, in England, with the fire of the latest Whitworth and Horsfall guns have shown that, even before the first large and expensive fleets of armored ships built by the United States, France, and England, are fairly brought into service, a considerable portion of them all, but more especially (it would appear) of those of the two countries last named, are no better against guns that can now at anytime be brought to bear upon them, than the old wooden walls; since the former would have, as certainly as the latter, to rely on speed and Page 628 manoeuvring to escape near direct firing, and so to prolong their existence and power of aggression. The result in England has been a suspension of opinion in reference to the effectiveness of practicable iron armor, and more than this, the questioning by some authorities whether any effective armoring is not in the nature of the case an impracticable thing. In this country, the same degree of distrust on this question has not arisen; and the greater confidence existing must be traced in no inconsiderable degree to the fact of the general choice here of models for armored vessels, and plans of armoring that, for the purposes intended and the tonnage and capacity given, have unquestionably, nay, demonstrably, proved more decided successes and steps of advance in practical naval warfare, than have any or all the armored ships thus fur produced by France and England. There can be little doubt that, for their tonnage, the Roanoke and Dunderberg will prove quite as formidable antagonists as any of the Royal Oak and Prince Consort class of English (similar) plated wooden ships; nor that the Puritan and Dictator, with their l0 ½ -inch armor and four feet of oak, but practically backed also with the entire remaining deck of 40 ft. breadth, its own thickness of the sides only rising above water, will be almost absolutely invulnerable; while it must, at the least, be admitted that, when completed, those will be beyond comparison the most formidable war vessels in the world. The enduring capacities of even the smallest-size Monitors are proved abundantly by the absolute freedom from penetration and the slight actual damage with which seven of them came out from the terrific hail of projectiles poured upon them for more than an hour in Charleston harbor; and the assurance is given that even this class can be practically much further strengthened, to meet future assaults.

Still, these smaller vessels are valuable only for their purposes, and within a certain sphere of service. Mr. McKay justly urges that, while they are well fitted for defending or operating in harbors, they cannot command the high seas, take the necessary part in great naval engagements, break blockades on distant coasts, nor protect our commerce in remote parts of the world; and he anticipates that in a contest with large iron-clad frigates, they would be terribly handled, and would probably be run down. He calls attention to the fact that the French will soon have a fleet of 16 iron-cased frigates fit for foreign service and an aggressive warfare, the English 16 such frigates and 2 iron-cased corvettes, suitable for the like purposes. It may still be answered that, if the true policy of this country be anticipated to continue a defensive one, then her war navy is increasing in strength in the right direction. But Mr. McKay argues that, to be compelled to keep on the defensive is in itself a defeat; and yet, that fur such purpose only, in case of a war with any of the great naval powers, it is absolutely necessary that we have at least 20 large, powerful iron-cased frigates, that can be used also as rams, of at least 12 knots speed, capable of carrying ten days' coal, and in draught not exceeding 24 feet. These ships, he thinks, should be of wood, and copper bottomed, while, besides these, there would be need of 20 to 30 armored shell-proof corvettes, of high speed and light draught, and carrying each 10 to 12 guns.

Perhaps the practical conclusions following from the whole subject, in reference to the improvements now appearing desirable, both in the line of ordnance and of armored vessels, cannot better be expressed than in the language of Mr. Holley, in the "Atlantic Monthly," for January, 1863,—in an article from which, as well as from that by the same author in the "National Almanac," for 1863, some of the facts and deductions given in this paper, and not separately credited, have been drawn— when he says: "The direction of immediate improvement in ordnance for iron-clad warfare appears to be in the abandonment of cast iron, except as a barrel to be strengthened by steel; binding an inner tube with low-steel hoops, having a successively increasing initial tension; and the use of spherical shot at excessive velocities by means of high charges of powder in bores of moderate diameters [rather, it would appear on this point, in bores of the largest possible diameters for which the due strength of metal to boar the proportional firing charge can be secured]. The rifling of some guns is important, not so much to secure range or accuracy, as to fire elongated shells through armor. The direction of improvement in [large iron-clad vessels, appears to be in the concentration of armor," with shot-proof decks and bulkheads, as already described; "high speed without great increase of weight of the driving parts, by means of improved engines and boilers, and high pressure; the production of tenacious iron in large, thick, homogeneous masses; and the rapid manoeuvring of heavy ordnance by machinery."

Finally, even if it should not appear altogether apposite to our subject, it is certainly apposite to man, who is still greater in himself than all the wonderful things he can do, and more important to himself than all that he can accomplish in his Titanic play with matter and forces, to add from a moral point of view the reflection that, to accept the struggle now going on between the means of offensive and of defensive warfare as an end, or as anything indeed more than a passing disturbance or convulsion running through the human mind and over the face of society, would be to put a wholly new interpretation henceforward upon the meaning and intention of all scientific advancement, and upon that more authoritative presage of nearly nineteen centuries since, conveyed in the words " On earth peace, good will toward men." (The American Annual Cyclopaedia and Register of Important Events of the Year 1861, vol. 1. New York: Appleton & Co., 1868, pp. 604-629.)


Source: The American Annual Cyclopaedia and Register of Important Events of the Year, 1861-1865, vols. 1-5. New York: Appleton & Co., 1868.