TRANSACTIONS OF THE SECTIONS. 49 



beet quality, iu regard to lightness combined with strength and toughness, is lead- 

 ing to its very advantageous employment in the construction of a particular class of 

 vessels for the Navy ; and the perfect confidence which can he placed in the unifor- 

 mity, in structure and strength, of steel of such character as is produced by the 

 Whitworth system of manufacture has greatly facilitated the production of air- 

 chambers of small weight, but capable of being quite safely charged with sufficient 

 air, under a pressure of 1000 lb. on the square inch, to carry the Whitehead tor- 

 pedo through water to the distance of a thousand yards in little more than a 

 minute and a half. 



Thus the results of the recent development of the steel-industry, to which the 

 labours of the chemist have not unimpi irtantiy contributed, give promise of exerting 

 a great influence upon the resources of nations for defence and attack. Although 

 the necessity for the continual expansion of such resources cannot but be deeply 

 deplored, there can be no doubt that the problems which it presents, and the 

 special requirements to which it gives rise, must operate, and perhaps as importantly 

 as the demands created by peaceful industries and commercial enterprise, in en- 

 couraging the metallurgist, the chemist, and the engineer to continue their com- 

 bined work in following up the successes, to the achievement of which the results 

 of scientific research have greatly though indirectly contributed. 



If it were necessary to add to the illustrations which Mr. Perkm gave in his 

 Address last year of the practical fruits of research in organic chemistry, I might be 

 tempted to dilate upon the important results which have, especially during the last 

 ten years, grown out of the discovery and study of the products of the action of 

 nitric acid upon cellulose and glycerine. During the six years which have elapsed 

 since I had the honour of bringing before the members of the British Association 

 the chief points of scientific interest and practical importance presented by the his- 

 tory of those remarkable bodies, their application to technical and war purposes has 

 been greatly developed. Nitroglycerine and gun-cotton may now be justly classed 

 among the most interesting examples of the practical importance frequently 

 attained by the results of chemical research, while the history of the successive 

 steps by which their safe manipulation and efficient application have been developed 

 affords more than one striking illustration of the achievements effected, by com- 

 bined physical and chemical research, in the solution of problems of high scientific 

 interest and practical importance, and in the vanquishment of difficulties so for- 

 midable as, for a time, to appear fatal to the attainment of permanently practical 

 success. 



It is to a careful study of the influence which the physical characters of gun- 

 powder (its density, hardness, &c.) and its mechanical condition (/. e. form and size 

 of the masses and condition of their surfaces) exert upon the rapidity of the ex- 

 plosion under confinement that we chiefly owe the very important advance which 

 has been made of late years in controlling its explosive force, in its application as 

 a propelling agent, and the consequent simple and effectual means whereby the 

 violence of action of the enormous charges now used in siege- and ship-guns is 

 effectually reduced to within their limits of endurance, without diminution of the 

 total explosive force developed. But, concurrently with these important practical 

 results, the application of combined chemical and physical research to a very ex- 

 tended and comprehensive investigation of the action of fired gunpowder has 

 furnished results which possess considerable interest from a purely scientific point 

 of view, as in many respects modifying, in others supplementing, the conclusions 

 based upon earlier experiments and theoretical considerations with respect to the 

 nature and proportions of the products formed, the heat developed by the explosion, 

 the tension of the products of combustion and the conditions which regulate it, 

 both when the explosion is brought about in a close vessel and when it occurs in the 

 boreofaguu. The residts of these physico-chemical researches have, moreover, 

 already acquired practical importance in regard to the light they have thrown upon 

 the influence exerted by variable conditions of a mechanical nature upon the action 

 of, and pressure developed by, fired gunpowder iu the bore of a gun, and in demon- 

 strating that modifications in the composition of gunpowder, not unimportant from 



