STEEL CYLINDERS FOR GUN CONSTRUCTION- 
STRESSES DUE TO INTERIOR COOLING. 
BY 
Rogers Birnie. 
[Read before the Society May 11,1895.] 
This experiment is the first important step taken by the 
Ordnance Department of the United States Army to inves¬ 
tigate the merits of making cannon from a single steel forg¬ 
ing with initial tension produced by interior cooling. The 
experiments of similar import with reference to built-up or 
hooped steel guns which were made by this department in 
1884-6 established on a very firm basis the manufacture in 
this country of that description of gun, and it is not im¬ 
probable that the present investigation may lead to equally 
important results for the single forging construction. 
The inception of this work is due to Captain Frank Hobbs, 
of the Ordnance Department, and the experimental forging 
was furnished, through his instrumentality, by the Bethle¬ 
hem Iron Co. The subject has received attention in other 
places, particularly in the interesting work of General 
Nicholas Kalakoutsky,* of the Russian artillery, but up to 
this time guns have not been made upon the plan proposed. 
At Le Creusot, France, interior cooling has, however, been 
used to improve the condition of cylinders used in built-up 
guns. As to the treatment of the forging, it may suffice to 
say that its preparation was similar to that of a forging in¬ 
tended for a hooped gun, by the usual methods of casting, 
* Kalakoutsky (General Nicholas). Investigations into the internal 
stresses of cast iron and steel. London, George Reveirs, 1888. 
13—Bull Phil. Soc., Wash., Vol. 13. 
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