504 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



fire, and sulphur burns at a lower temperature, so that we must 

 wait for the wood of the match to be ignited before we can light 

 an oil lamp. If we could instantly convert a particle of ice into 

 steam, it would be as useful as gunpowder. But whatever we 

 undertake to substitute for gunpowder must be readily inflamed, 

 and, at the same time, become sufficiently heated. 



Prof. Seely. — The amount of heat produced by combustion 

 depends upon the amount of oxygen consumed. There is no 

 substance which produces so much heat in combustion as hydro- 

 gen. We find they combine : 



Hydrogen 1 Oxygen.. 8 Seg 1:8 



Carbon 1 do 3^ 1:3.5 



Sulphur 16 do 32 1:2 



Phosphorus 32 do 40 1:1.25 



And this is the order in which they produce heat. There is 

 another property of sulphur, also very important : its volatility, 

 and the readiness with which it communicates a flame from one 

 particle to another. This causes a large volume of powder, in 

 small grains, to be ignited very rapidly, there being a large sur- 

 face which the flame covers. 



Mr. Roosevelt suggested that as it takes more than a man's 

 weight in lead to kill a man, gunpowder is only a humbug after 

 all, and the bayonet the proper weapon for an effective army. 



Mr. Johnson suggested a new mode of making large iron tubes 

 for guns, hydraulic presses, and other articles requiring great 

 tenacity. 



At present it is the practice in most cases to bore the cavity 

 out of a solid mass of metal, whether obtained by casting or 

 forging. Mr. Johnson would propose, instead, to form the tube 

 upon a mandril, beginning by rolling upon it a red hot sheet of 

 wrought iron. Upon this he would sprinkle, while hot the 

 Franklinite iron, with borax, covering the layer with a second 

 sheet of red hot wrought iron, and continuing thus to apply suc- 

 cessive layers of sheet iron and Franklinite until the thickness 

 necessary for strength is reached. The mandril being withdrawn, 

 the tube heated to the welding point, is next to be passed through 

 rollers, by which action, as the Franklinite is liquid at that tem- 

 perature, the excess of that material will be pressed out, and the 

 whole mass firmly united. 



To avoid clogging the mandril, the first cylinder of iron 

 applied to it had better be a steam or gas pipe. 



