1856.] of Chemistry to Mliiary Pvrposes. 287 



an economic point of view, provided it were required for rapid 

 consumption. 



Some preliminary experiments lately instituted by the speaker, 

 with the view to examine into the nature of the decomposition of 

 a variety of powders, had shown that the residue left on the ignition 

 of some of the best prepared specimens (composed of the ingre- 

 dients in the proportions indicated by theory) contained appreciable 

 quantities of nitric acid; and that the amount of charcoal remaining 

 after the decomposition of such powders formed, in many instances, 

 an important proportion of the total quantity contained in the powder. 

 These circumstances indicated that the manufacture of powder 

 was still susceptible of some improvements, which should tend to 

 render the mingling of the ingredients more perfect. Some patented 

 modifications of the so-called incorporating process were alluded 

 to, which appeared, from trials made with them, to be steps in the 

 right direction. 



Mr. Abel stated that, after an extensive series of experiments, 

 it had been determined to substitute for the tedious process of 

 refining saltpetre, hitherto adopted at Waltham Abbey, by repeated 

 recrystallizations, the more expeditious and economical and equally 

 efficient method in use upon the Continent, which consists in causing 

 the saltpetre to be rapidly deposited in minute crystals from a hot 

 solution, by maintaining the latter in constant motion till cool ; in 

 draining thoroughly the so-called saltpetre-flour^ and in removing 

 the adherent impurities by two or three successive washings, first witli 

 the wash-water from former operations, and finally with pure water. 



In conclusion, reference was made to the employment of other 

 explosive and inflammable mixtures, differing in their composition 

 more or less widely from gunpowder. These might be classed 

 under three heads : Firstly, those consisting of the ingredients of 

 gunpowder in varied proportions, examples of which were the 

 compositions for fuses and rockets ; secondly, those employed as 

 incendiarj' or smoke-producing agents, in the preparation of which 

 such materials as resin^ bituminous coal, pitch, boiled oil, Venice 

 turpentine, zinc, and antimony, were employed, in addition to the 

 gunpowder-constituents ;* and thirdly, those which contained metals 

 or metallic compounds capable of imparting to flame various tints, 

 and which were employed as signal-lights, or for pyrotechnic com- 

 positions. 



* It is very generally known that numerous propositions have been sub- 

 mitted to Government, during the war, for the employment of coal-tar naphtha 

 as an incendiarj- material, and for applying, as agents of destruction, not only 

 some of the most inflammable, but also many of the most poisonous substances 

 known to chemists. None of these have, however, met with application ; 

 partly from the difficulties encountered in contriving means for the safe trans- 

 port and application of the most effective of such agents ; and partly from the 

 natural hesitation of military men to have recourse to such novel weapons of 

 destruction. 



Vol. II. n 



