Chemical Preparations. 293 
rated, and left the powder entirely free from adventitious matters. 
A few hundred pounds were made by grinding impure materials in 
pure oil of turpentine, and a sample is inclosed in the box. ‘The advan- 
tages to be derived from this project, if any, are, 1st. It will obviate all 
danger of explosion in uniting the materials, for a coal of fire, if not 
in flame, will be promptly extinguished if immersed in the composi- 
tion whilst in the act of grinding ; and 2d. A better powder may be 
made with less machinery, than can be made by the usual process ; 
because the texture of the ingredients can be more effectually broken 
down. The disadvantage of the process is the additional cost of 
whatever turpentine is lost in the operation, which I think would be 
some ten or twelve cents in a quarter cask of twenty-five pounds. I 
think well of the process, and shall give it a thorough trial. 
4. FuLMINIC ACID AND FULMINATES. 
+ 
I was greatly surprised to-day, and somewhat chagrined, by read- 
ing your observations on fulminic acid, &c., to find myself anticipated 
inwhat I was about to claim as a discovery of my own, to wit, that 
fulminic acid could be transferred to caustic potash, and a salt ob- 
tained from the union ; and that that salt, at less than a boiling heat, 
would be decomposed, and yield ammonia. I have been occupied 
with the subject these two weeks, and beg leave to request you to re- 
peat the following experiment; and to give you the least possible 
ttouble, I have sent you a small phial of fulminating mercury, covered 
by water. If the subject be familiar to you, it will have no interest ; 
fnot, I think it will have enough to repay the trouble of making the 
experiment. 
Into a wine glass put a quantity of fulminating mercury merely 
Wet, but with no water standing upon its surface—then pour upon it 
’§ much saturated solution of caustic potash as shall make it into a 
Paste—in an hour or two it will be found to be thick and stiff. 
Dilute it again and again until it shall cease to become stiff, which 
will be, probably, at the end of forty eight hours—it will then have 
’equired four times its original bulk. At the end of the first day 
lake out a small parcel of the composition, and wrap it in a piece of 
®ommon factory cloth and press it as dry as possible, between two 
Small pieces of boards, in a blacksmith’s vice or other powerful press. 
must then be dried on an iron plate, drawn from boiling water, 
Which heat it will probably bear—if not, it will bear 200°. A few 
stains only should be dried at once, and this dried as near its ex- 
