‘ 
190 Miscellanies. 
portions 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; solu- 
tion of potash and fragments of calomel ; solution of iodide of potash 
and chloride of lead; solution of muriate of lime and erystals of car- 
bonate of soda; solution of per-sulphate of copper and crystals of 
ferro-cyanate of potash,—from these experiments it would appear, 
Mr. Faraday observes, “ that there is no reason to believe that water 
or its vapors confer volatility, even in the slightest degree, upon those 
substances which alone have their limits of vaporization at tempera 
tures above ordinary occurrence, and that consequently natural evap- 
oration 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 aml 
monia, are substances which evolve vapor at common temperatures.” 
(Journal of the Royal Institution, October, 1830.)—Phil. Mag. and 
Ann. Nov. 1830. 
= 
“ 
13. Composition of gunpowder.—Dr. Ure has analyzed various 
samples of gunpowder, and the following are the results of his inve* 
tigation : 
Waltham Abbey—nitre, 74.5 ; charcoal, 14.4; sulphur, 10. ; water; 
Hail, Dartford—nitre, 76.2; charcoal, 14.; sulphur, 9.0; water, 
-5; loss, . 
Pigou & Wilkes—nitre, 77.4; charcoal, 13.5; sulphur, 8.5; ¥* 
ter, . 
Curtis & Harvey—nitre, 76.7; charcoal, 12.5; sulphur, 9.3 wateh 
Lids 6ee, oz 
Battle gunpowder—nitre, 77. ; charcoal, 13.5; sulphur, 8.5 watels 
-8; loss, . 
“The process,” observes Dr. Ure, “ most commonly practised in 
the analysis of gunpowder seems to be tolerably exact. The pitre 
is first separated by hot distilled water, evaporated and weighed. — 
minute loss of salis may be counted on from its known volatility, with 
boiling water. I have evaporated always ona steam bath. Itis pr? F 
able that a amall proportion of the lighter and looser constituem's e 
gunpowder, the carbon, flies off in the operations of corning and, dus 
