384 Intelligence and Miscellaneous Articles. 



In September 1826, several stoppered bottles were made per- 

 fectly clean, and several wide tubes close at one extremity so as to 

 form smaller vessels capable of being placed within the bottles, were 

 prepared. Then selected substances were put into the tubes, and so- 

 lutions of other selected substances into the bottles : the tubes were 

 placed in the bottles so that nothing could pass from the one sub- 

 stance to the other, except by way of evaporation. The stoppers were 

 introduced, the bottles tied over carefully and put away in a dark safe 

 cupboard, where, except for an occasional examination, they have 

 been left for nearly four years, during which time such portion of the 

 substances as could vaporize have been free to act and produce 

 accumulation of their specific effects. 



In this way it was found that neither sulphate of soda nor muriate 

 of barytes were volatilized ; the same was the case with solution of 

 nitrate of silver and chloride of sodium ; diluted sulphuric acid and 

 common salt ; solution of potash and arsenious acid in pieces and 

 powder ; diluted sulphuric acid and muriate of ammonia ; solution of 

 persulphate of iron and ferrocyanate of potash in crystals ; solution 

 of potash and fragments of calomel ; solution of iodide of potash, and 

 chloride of lead ; solution of muriate of lime and crystals of carbonate 

 of soda ; solution of persulphate of copper and crystals of ferrocya- 

 nate of potash; — from these experiments it would appear, Mr. Faraday 

 observes, " that there is no reason to o believe that water or its vapours 

 confer volatility, even in the slightest degree, upon those substances 

 which alone have their limits of vaporization at temperatures above 

 ordinary occurrence, and that consequently natural evaporation can 

 produce no effects of this kind on the atmosphere." 



From other experiments, Mr. Faraday concludes that "nitrate of 

 ammonia, corrosive sublimate, oxalic acid, and perhaps oxalate of 

 ammonia, are substances which evolve vapour at common tempera- 

 tures." — Journal of the Royal Institution, October, 1830. 



COMPOSITION OF GUNPOWDER. 



Dr. Ure has analysed various samples of gunpowder, and the follow- 

 ing are the results of his investigation : 



Nitre. Charcoal. Sulphur. Water. Loss. 



Waltham Abbey 74-5 



Hall, Dartford 76-2 



Pigou and Wilks ... 77'4 

 Curtis and Harvey. . 76'7 

 Battle gunpowder . . 77*0 

 " The process," observes Dr. Ure, " most commonly practised in 

 the analysis of gunpowder seems to be tolerably exact. The nitre is 

 first separated by hot distilled water, evaporated and weighed. A 

 minute loss of salt may be counted on from its known volatility with 

 boiling water. I have evaporated always on a steam bath. It is pro- 

 bable that a small proportion of the lighter and looser constituent 

 of gunpowder, the carbon, flies off in the operations of corning and 

 dusting. Hence analysis may show a small deficit of charcoal below 



the 



144 



100 



1-1 





140 



9-0 



0-5 



03 



13-5 



8-5 



0-6 





12-5 



9-0 



1-1 



0-7 



13-5 



8-0 



0-8 



07 



