200 Krupp’s Steel Works at Essen. 
during hot weather; but the energy of Mr. Krupp has 
carried all before him, and by extra pay for heavy work, 
and exciting their undoubted esprit de corps, they have been 
brought to face anything, though many of them have 
fainted under the trial, when large castings have necessarily 
been made in hot weather. 
HAMMERING. 
However elaborate an article is intended to be produced, 
the ingot is cast in a cylindrical or square form, hammered 
out to the rough shape required, and then turned, &c., to 
exact dimensions. Large castings made of irregular con- 
tour would not be homogeneous, and might contain air 
bubbles. When required for manufacture the ingot (if 
such masses as Krupp casts can be called ingots) is placed 
under a steam hammer, of size proportionate to the weight 
of metal required to be drawn out; and the gun, shaft, or 
whatever it may be, grows to its form by long-continued 
work, being retained at nearly the same temperature (cherry 
red) by frequent heats. This solidity of casting gives 
soundness, and the heavy hammering received by the metal 
increases its density, strength, and elasticity. The con- 
densing effect of the hammering causes an increase of 02 
to 0'3 in the specific gravity of the ingot, though it may 
have no holes when first cast. Small castings, such as 
rails, &c., are rolled in mills, exactly similar to ours, except 
that the rollers are cast steel When the metal has been 
fully worked its breaking strain varies from thirty-six to 
sixty-six tons on the square inch, according as it is soft or 
hard. That best for guns is rather soft and has a strength 
of about forty-four tons, or even less. 
GUNS. 
The smaller natures of guns are fashioned from one solid 
piece, those above 8-inch calibre are compound, being 
weighted and strengthened by jacket or rings. The II- 
inch, for instance, the largest steel gun yet manufactured, 
is cast as a cylinder, weighing thirty-five tons, and of seven 
feet diameter, hammered out toa shape of sufficient strength 
to bear proof charges, being turned down to a thickness 
over the charge of one calibre. The trunnion-ring, which 
is also a cast steel cylinder forged into the form required, 
is then shrunk on, and the breech strengthened by the ad- 
dition of several hoops, also of cast steel, forged as usual, 
to a breadth of 10-inches and a thickness of 6-inches. Two 
