involved in the Construction of Artillery. 



215 



cate guns of German steel, seem a step in a wrong direction, and made in 

 ignorance or in defiance of the first principles that should guide us. (NoteM.) 

 142. The following Table will make this conclusively clear for the material 

 in question : — 



Table VII. 



Kesisting Powers of the Cast- Steel of Herr Kmpp, Essen, Westphalia, as compared with other 

 Metals for consti-uctivg Ordnance. From Report hy the Prussian Ministry of War, Berlin. 



No. 



MeUL 



Krupp's Cast-Steel, No. 1 (Ein kron), 



„ 2 



„ 3 

 "Wrought-Iron, „ 1 . , 



„ 2 . . 



Cast-iron, 



Gun-Metal, 10 per cent. Tin, , 

 9 „ „ . 



11 „ „ . 



12 „ „ . 



Angle of 



Torsion ; Value of Tr 

 before , deduced. 

 Rupture. 



Deps. 

 207° 

 182° 

 221° 

 322° 



12° 



400° 

 386° 

 315° 

 130° 



3757050 

 3-652-740 

 3-825-510 

 4028-220 



105-060 

 4 086000 

 4 016-330 

 3-200-400 

 1-189-500 



Note The direct tension experiments were made by Lieutenant-Colonel Orges, at Bnmswick, ou |-inch 



« square bars, by means of an hydraulic-press pro\Tng machine ; the experiments on torsion, by Lieut.- 



Culonel Weber. The Report erroneously deduces from his results, that Krupp's steel has an approximate 

 stability (Festigkeit — quere Zkhiglieit':'), the double of that of the best bronze. 



143. On examining the third column of this Table it will be observed that 

 the ultimate cohesion of German cast-steel is nearly twice as great as that of 

 wrought-iron, six times as great as that of cast-iron, and from two and a half 

 to three times as great as that of gun-metal ; and this, looked at alone, would 

 appear to sanction the high value attributed to the first, as the best material for 

 artillery; but when we examine the sixth column, in which the "work done" 

 in overcoming the resistance of column 4, through the space due to the angle 

 of torsion, is given, we find the startling result, that this is greater for wrought- 

 iron, and even for the best gun-metal, than for the best cast-steel. Nothing 

 can more clearly show the unfitness of steel, and the extreme suitability of soft 

 wrought-iron. for making cannon. 



The cast-iron in this Table must have been extremely hard, probably a 



2f 2 



