NAVY, UNITED STATES. 



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 Liver- 

 pool. Among the experiments made to test the 

 value of this plan, were those in England, in 

 1861, in which a 3J-inch solid plate fixed at an 

 angle of 45 was more injured by elongated 

 100-lb. shot, than a 4^-inch solid plate in a verti- 

 cal position, the two plates having the same 

 backing and equal weights of metal in the same 

 vertical height. In fact, the Iron Plate Com- 

 mittee have recently reported that with any 

 practicable inclination from the upright as 

 much as 52 it takes the same weight of iron 

 to cover effectually with armor a certain 

 length and height of side, whether this be in- 

 clined 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 state- 

 ments must, however, be to some extent quali- 

 fied, both for the form of projectile and sort of 

 gun, on one hand, and for the relative hard- 

 ness 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 be- 

 ing from any cause once "ended over" or 

 glanced. With projectiles of such form, rifling 

 appears indispen sable, in order to give per- 

 sistency in direction of flight, and to keep 

 them on end while cutting into armor. And 

 in such case, especially if the shot be hard- 

 ened 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, fur- 

 ther, if the shot are glanced, and often in that 

 case in fragments, they must prove so destruc- 

 tive to objects on deck as to render masts, rig- 

 ging, and sails unavailable. Round shot, in- 

 deed, 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 coun- 

 try, a 64-inch laminated target, vertical, was 

 by a 125-lb. spherical shot indented about 4 

 times as deeply as 6 J-inch plate, also laminated, 

 fixed at an angle of 275. Besides the disad- 

 vantages 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 aban- 

 doned. Since, on the part of the armor, a sur- 

 face at once highly hard and tough must in- 

 crease 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. Richard- 

 son 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 to- 

 ward that from which they came. He makes 

 the portholes either circular or oval, and con- 

 tinues the circular lip round them, so that shot 

 glancing over the surface of the shield may be 

 deflected from this also. Mr. J. TV. 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 Back- 

 ing. 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-con- 

 ducted 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 tb.6 thinner ones, and re- 

 marks 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 im- 

 perfection of the union there formed, Mr. 

 Holley regards the experiments as showing so 

 great a difference, in simple and absolute resis- 

 tance 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 ap- 

 plication, are the plates of laminated armor ; 



