1874.] on Fired Gunpowder. 411 



up as rapidly as possible. In most cases, during the very short time that 

 elapsed while the transference was being made, no apparent change took 

 place ; but, in some, a great tendency to development of heat was appa- 

 rent ; and in one instance, in which a portion of the deposit (exhibiting 

 this tendency in a high degree) was kept exposed to the action of the air, 

 the rise of temperature was so great that the paper on which it was 

 placed became charred, and the deposit itself changed colour with great 

 rapidity, becoming a bright orange-yellow on the surface. 



This tendency to heat always disappeared when the deposit was con- 

 fined in a bottle and fresh access of air excluded. 



The methods employed in the analysis of the gaseous and solid products 

 of explosion differed only in a few respects from those adopted by 

 Bunsen and Schischkoff in their investigation of the products of explosion 

 of powder. 



As regards the proportions of total solid and gaseous products fur- 

 nished by the several powders, remarkable uniformity was exhibited by 

 the results of explosion of the same powder at different pressures, and no 

 very considerable difference existed between the proportions furnished by 

 the three powders chiefly used in the researches. The largest grain, or 

 pebble powder, yielded most gas ; the quantity furnished by ft. L. Gr. 

 powder was not greatly inferior, but was decidedly more considerable 

 than that yielded by the smallest powder (P. Gr.). 



The composition of the gas furnished by the explosion of all the Eng- 

 lish powders was throughout remarkably uniform, but presented certain 

 apparently well-defined small variations, regulated by the pressure under 

 which the products were developed, the chief being a steady increase in 

 the proportion of carbonic anhydride, and decrease in that of carbonic 

 oxide, in proportion as the pressure was increased. The composition of 

 the solid products exhibited much greater variations, chiefly in regard to 

 the state of combination in which the sulphur existed. These variations 

 were exhibited not merely by the products obtained from the different 

 powders, but also, and to as great an extent, by those which one and the 

 same powder furnished at different pressures, and apparently without 

 reference to the pressure, excepting in the case of the very lowest 

 (the powder occupying 10 per cent, of the total space in the chamber). 



The authors institute a comparison between the composition of the 

 products of explosion obtained in their experiments and the analytical 

 results published by Bunsen and Schischkoff and other recent experi- 

 menters, and proceed to a critical examination of the methods pursued by 

 these for obtaining the products of the composition of gunpowder, giving 

 reasons why the results which those methods of operation have furnished 

 cannot be accepted as representing the changes which powder undergoes 

 when exploded in a closed space. 



The authors further proceed : It is evident that the reactions which 

 occur among the powder-constituents, in addition to those which result 



