400 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



up of the progress made upon this subject within the last year 

 in this country ? 



Mr. Babcock. — Not much. That sums it up briefly. 



The Chairman. — Is it true that the government of the United 

 States is not at any point manufacturing the best and most 

 approved cannon in use ? 



Mr. Babcock. — They are now rifling cannon on Governor's 

 Island. An old cannon rifled is just as good as a new cannon 

 rifled. At the Washington Navy Yard they have been manufac- 

 turing rifled cannon several years under Capt. Dahlgren's suj)er- 

 vision. 



Mr. Seely called attention to other explosive compounds than 

 gunpowder. Gun cotton can be made more or less explosive 

 than powder. In some respects it has advantages over gun- 

 powder ; but it explodes at so low a temperature, about 300 

 degrees, and the products of its combustion are so corrosive, that 

 it is not much used. It might be made serviceable, for example, 

 in charging a bomb. There is a composition called white gun- 

 powder, which has been found to expand one-third more than 

 ordinary gunpowder. There are very explosive compounds, 

 which produce violent effects within a verj^ short distance; but 

 the amount of expansion is so little that they would be utterly 

 unfit for gunpowder. Chloride of nitrogen, for instance, will 

 shatter the plate beneath it to a fine powder ; but, beyond that, 

 has very little effect. 



Mr. Johnson, to show that iron could remain good after long 

 heating, cited the case of the wrought-iron gun made at Liver- 

 pool in 1857 — a gun weighing twenty-five tons before it was bored, 

 and which it required seven weeks to forge. The diameter of 

 the bore was 13.05 inches, and the iron which came out of the 

 centre Avas perfect iron. 



STEEL GUXS. 



Mr. Nash said that it had been found, by experiment in Paris, 

 that a cannon made of cast steel would throw balls 13,000 yards. 

 This was the official report of the gunners. 



Mr. Babcock. — The French steel guns are made with a ham- 

 mer weighing ten tons, and falling ten feet. Here we have guns 

 made of cast-steel, or of a semi-steel, instead of hammering. 



Mr. Dibben. — The process of welding pieces of blistered steel 

 is the method pursued for hammered steel guns. The pieces are 



