II. Researches on explosives.—Fired gunpowder

Abstract

The investigations which form the subject of this memoir have occupied our attention for a considerable time, having been commenced in 1868. They have been made collaterally with a series of experiments carried on by a Committee appointed by the Secretary of State for War, with the view, among other objects, of determining the most suitable description of powder for use in heavy ordnance, which is still continually increasing in-size; indeed our main object has been to endeavour to throw additional light upon the intricate and difficult subject under investigation by that Committee. There are perhaps few questions upon which, till within quite a recent date, such discordant opinions have been entertained as upon the phenomena and results which attend the combustion of gunpowder. As regards the question alone of the pressure developed, the estimates are most discordant, varying from the 1000 atmospheres of Robins to the 100,000 atmospheres of Rumford; or even, discarding these extreme opinions in favour of views which have been accepted in modern text-books as more reliable, the difference between an estimate of 2200 and of 29,000 atmospheres is sufficiently startling as regards a physical fact of so much importance. The views regarding the decomposition of gunpowder are nearly as various; and we therefore think that a description and discussion of our own researches may be usefully preceded by a short account of the labours of the previous investigators of this subject and of the grounds upon which their conclusions were based.