Chemical Preparations. 289 
You will find a bottle containing some condensed fumes, arising 
during the preparation of fulminating mercury. Iam now satisfied 
that the fumes contain spirits of nitrous ether, nitrous acid and mer- 
cury, and some uncondensable gas or gases, and vapor of water. 
Sixteen measured ounces of alcohol give ten measured ounces of 
condensed fluid. I have ascertained that nitric acid, of sp. gr..1.34, 
can be made to compensate for its weakness, by increasing the pro- 
portion of it to the mercury and alcohol. One hundred grains of 
mercury, to two measured ounces of acid of this strength, and two 
measured ounces of alcohol, made as good fulminating mercury as 
Ihave ever seen. 
Isend you two small phials of nitrated sulphuret of potash, or yel- 
low powder, as it is usually called in this country. _ It is far less per- 
fect than such as I used to make, when in the habit of preparing it 
some years ago. You will perceive by burning it, in small parcels, 
upon the hearth or otherwise, that it takes fire with readiness, and 
burns much quicker than common powder. I have made some 
hundred pounds of it, which were eagerly bought up by hunters and 
‘portsmen for priming fire arms, a purpose which it answered most 
admirably ; and, but for the happy introduction of powder for prim- 
ing, which is ignited by percussion, it would long since have gone into 
extensive use. 
_ With this preparation I have had much to do, and I doubt whether, 
ia the whole circle of experimental philosophy, many cases can be 
found involving dangers more appalling, or more difficult to be over- 
“ome, than melting fulminating powder and saving the product, and 
reducing the process to a business operation. Ihave had with it 
“me eight or ten tremendous explosions, and in one of them I re- 
ceived, full in my face and eyes, the flame of a quarter of a pound 
ot the composition, just as it had become thoroughly melted. 
€ common proportions of 3 parts of nitre, 2 parts of carbonate 
of potash and 1 part of sulphur, gave a powder three times quicker 
than Common black powder; but, by melting together 2 parts of 
Rees and 1 of carbonate of potash, and when the mass was cold 
udding to 43 parts of it, 1 part of sulphur—equal in the 100, to 54.54 
ary nitre, 27.27 dry carbonate of potash and 18.19 sulphur—a great- 
“uperior composition was produced, burning no less than eight and 
one half times quicker than the best common powder. The substan- 
CS Were intimately ground together, and then melted to a waxy con- 
“slence, upon an iron plate of one inch in thickness, heated over a 
OL, XX] oe. 4 
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