16 MEMOIR ON THE 



Rifle powder, gas evolved, . . . . . . 51^ cubic inches. 



" " absorbed, 20^ " 



Sporting powder, average of two experiments. 



Gas evolved, . . . . . . 51 cubic inches. 



" absorbed, 25 " 



30. As the gas left after the removal of the carbonic acid had all the negative 

 characteristics of nitrogen, it may be concluded from the results above given, that 

 the gaseous products of deflagrated gunpowder consist of nearly equal volumes of 

 carbonic acid and nitrogen. 



31. I was naturally led to compare the results of the deflagration of gun-cotton 

 with those of gunpowder. Accordingly, I exposed a tuft of gun-cotton, weighing 

 twenty-five grains, in the exhausted receiver in a similar way. I found a retarda- 

 tion in the activity of the combustion arising, as in the case of gunpowder, from 

 the absence of mechanical confinement, diminution of atmospheric pressure tending 

 to lessen the contiguity indispensable to intense chemical reaction. 



32. The deflagration of the tuft being effected, it caused an evolution of gas 

 equal to 19^ cubic inches. 



33. In order to concentrate the combustible ingredients, resort was had to the 

 apparatus employed in the case of gunpowder, by which means twenty-five grains 

 of the cotton could be condensed into a cylinder of about half an inch in width, 

 and of a like length. 



34. Two specimens of gun-cotton, of the manufacture of Lennig, of fifty- four 

 grains each, prepared and ignited as above described, gave an evolution equal to 

 126 J cubic inches. 



35. As seventy-five grains of gunpowder gave only fifty-five cubic inches of gas 

 at most, it appears that equal weights being employed, gun-cotton causes a gase- 

 ous evolution more than three times as great as gunpowder. 



36. As seventy-five grains of gunpowder produces, taking the largest amount in 

 the above table, only fifty-five cubic inches of gas, it follows, that to produce an 

 effect equal to fifty-four grains of gun-cotton, one hundred and seventy-two and a 

 half grains of gunpowder would be requisite. 



37. The gunpowder evolved little more than seven-tenths of a cubic inch per 

 grain, while the gun-cotton evolved more than two cubic inches per grain. 



38. The gas arising from the gun-cotton did not admit of an examination so 

 simple as that given out by gunpowder. 



39. By the introduction of one hundred cubic inches of oxygen gas, it appeared 

 from the consequent red fumes, and absorption by water, that about thirty-five 

 cubic inches of nitric oxide had been formed : by the introduction of caustic pot- 

 ash, about twenty-five cubic inches of carbonic acid was indicated. One third of 

 the residual gas being exploded with oxygen, appeared to consist of three volumes 

 of hydrogen to four of carbon vapor. The washings gave indications of cyanogen. 



40. The coexistence of nitric oxide, carburetted hydrogen and cyanogen, in the 

 products, justifies the idea, that were the heat greater, the expansive effect would 

 be augmented by the transfer of the two atoms of oxygen in the oxide, to the 

 hydrogen and carbon, producing augmentation of temperature, carbonic acid and 



