Muriat of Potash. 241 
rounding air is, most probably, the cause of the 
loud reports produced by friction, &c. agreeably 
to the conclusions cf Berthollet; and the muriatic 
acid may remain combined with the potash, and a 
portion of the combustible substance employed :_ 
but when the sulphuric or nitrous acids are used, 
the muriatic acid is certainly disengaged. 
Since the above experiments were made, I have 
found that a paper has been read before the Na- 
tional Institute at Paris, on detonation by concus- 
sion, by citizens Fourcroy and Vauquelin.* They 
there mention some of the mixtures I have describ- 
ed, and their inflammation with the sulphuric acid. 
They likewise notice, that very loud reports and 
sparks were produced ona very small quantity of 
different mixtures being struck with a hammer on an 
anvil. This, on trial, I found to be the case; and 
a little cotton-wool well impregnated with the salt, 
being struck in that way, immediately took fire. 
But to get this to succeed, the salt and cotton should 
be perfectly dry: this is a necessary precaution in 
all experiments on the detonating property of this 
salt by friction, &c. Inthe paper above alluded to. 
it is stated, that sugar, the gums, fixed and volatile 
oils, alcohol and ether, do not detonate or take fire 
by simple trituration; but the experiments I made 
* Annales de Chimie, tom, xxi. Pp 295. © 
Nicholson’s Chemical Journal, I, p. 169. 
VOL. V. ; GCG 
