i66 



THE POPULAR SCIENCE MONTHLY. 



to purposes of protection, a style of construction now universally 

 adopted and known as cellular was developed by Sir E. J. Reed, 

 then chief constructor of the British Navy, in which the maxi- 

 mum of strength with the minimum of weight was sought after 

 and very fairly obtained. Then began, what has continued to 

 this day, the race between armor and armament; the makers 

 of armor striving to make plates that would effectually resist 

 the largest guns, and the gun-makers using every means at 

 their command to produce guns capable of breaking up or pene- 

 trating the heaviest armor. The outcome is, on the side of 

 armor, the solid steel plate with a face case-hardened by the 



Harvey process a face so hard 

 that no drill will in the slightest 

 degree affect it, and this extreme 

 hardness gradually shaded off to 

 a soft back to prevent through 

 cracks. On the other hand is the 

 steel built-up breech-loading gun, 

 with a length of from thirty-five 

 to forty-five times its diameter of 

 bore, using slow-burning powder, 

 having low initial pressures and 

 giving a muzzle velocity from two 

 thousand to twenty-five hundred 

 feet per second, and special steel 

 armor-piercing projectiles for the 

 purpose of racking or breaking up 

 the armor and then piercing the 

 hull. This competition has indi- 

 rectly opened up a new material 

 of some twenty per centum great- 

 er strength when compared with 

 wrought iron, known as mild steel, 

 FIG. 2. IOWA. Section through Armor, which naval architects are em- 

 ploying to enable them to produce 



lighter structures, and to use the weight saved in giving greater 

 thickness to the armor, increased armament, or added power and 

 speed, as the necessities of the design contemplated may demand. 

 Shortly after the introduction of this material, or in 1882, the 

 Congress of the United States appropriated for the construction 

 of three cruisers and one dispatch boat, which are now familiar to 

 us all under the names of the Chicago, Boston, Atlanta, and 

 Dolphin ; fortunately for our Government, its corps of naval con- 

 structors and engineers had by repeated visits to the ship-yards 

 and gun factories abroad, and a close study of the principles in- 

 volved in the new methods of construction, kept themselves fully 



