E X P L S I V E xV E S S O F N 1 T R E . 17 



aqueous vapor, In order to bring the explosive power of gun-cotton to its max- 

 imum, I infer that immense resistance would be necessary, thus concentrating and 

 expediting the reaction. 



41. The residue of the explosion of gunpowder appears, from a qualitative 

 analysis, to consist of sulpho-cyanide and sulphide of potassium, with carbonate 

 and sulphate of potash. The two latter are by much the more abundant products. 

 Probably sulphur is the primary and most energetic ingredient, as when in excess 

 it is, per se, known to be capable of completely decomposing potash at a moderate 

 heat, while carbon can only partially effect an analogous change at the highes 

 heat of a furnace. Faraday has recently alleged, that the production of the flame 

 of sulphide of potassium is an important agent in the explosive ignition of gun- 

 powder. It is likely that from the reaction of oxygen with sulphur and potassium, 

 a temperature results sufficiently high for the combustion of the charcoal with 

 oxygen, and of nitrogen with sulphur and carbon, whence ensues carbonic acid 

 and sulpho-cyanogen, in union with potassium in the one case, and with potash in 

 the other. 



42. I have already distinguished the explosion of mixtures like gunpowder from 

 fulminating combinations, of which the constituents being held together by intense 

 chemical affinity, require no mechanical confinement nor impact to bring or keep 

 them sufficiently near each other for reciprocal reaction. There is, however, 

 another distinction to be made. The explosion of vessels by high steam is alto- 

 gether the effect of heat and confinement. The resulting violence, when the 

 vessel bursts, is directly as its strength ; so that, knowing how many pounds per 

 square inch the vessel was capable of bearing, we know the explosive force to 

 have been exactly equal thereto. But the strength of the containing vessel, in the 

 case of gunpowder, may be very far short of that generated by the gunpowder 

 ignited within it. When held together until the temperature is attained which is 

 requisite for the play of affinities into which the ingredients are disposed to enter, 

 a sudden evolution of heat and gaseous matter takes place, producing a diruptive 

 force far beyond the retaining power of the vessel. 



43. Although gun-cotton is a chemical combination, consisting of nitric acid 

 and lignin, yet it does not explode, when unconfined, with a violence approaching 

 to that of other fulminating combinations above mentioned. This may be attrib- 

 uted to the fact that neither the elements of nitric acid, nor those of lignin, are 

 held together by a strong affinity, and consequently the forces which resist explo- 

 sion are but feeble. 



EXPERIMENT, 



OOMPARATiVE STRENGTH OF GUN-COTTON AND GUNPOWDER. 



Agreeably to some recent experiments made in my presence by Captain Mor- 

 decai, of the Regulars, at the U. S. Arsenal, Washington, at about thirty feet 

 distance, a cylinder of gun-cotton, weighing twenty-five grains, condensed as 



