168 Cautions, Sc. respecting Fulminating Powders. 
section of the union, a State legislature may thus providefor 
the protection of capital, engaged in enterprises of uncommon — m 
yisk, as well as of uncommon usefulness, without excluding 
other and better inventions, should they arise. 
~ Ishall ask leave to communicate, for some future Number, 
the results of experiments, now making, with the gas fire applied 
to engines. 
Iam your most respectful humble servant, 
JOHN L. SULLIVAN. 
Arr. XVI. Cautions regarding Fulminating Powders. 
Fulminating Mercury. 
D URING a late lecture in the laboratory of Yale College'a 
quantity of fulminating mercury, probably about 100 or 190 
grains, lay upon a paper, the paper lay on a small stool, 
which was made of pine plank, one inch and a half thick; a 
glass gas receiver, 5 or 6 quarts capacity, stood over the 
powder, as a guard, but without touching it, and stool and all 
stood on one of the shelves of the pneumatic cistern, SW 
rounded by tall tubes, and other glasses, several of which 
were within six or eight inches. A small quantity of the ful- 
minating powder, at the distance of a few feet, was merely 
flashed by a coal of fire, but without explosion. In @ manner 
“not easily understood, the whole quantity of powder under 
the large glass instantly exploded, with an astounding reports 
but the glass was not exploded—it was merely thrown Up ® 
little; in its fall it was shattered, and broke a glass whic 
it hit; but no fragment was projected, and none of the ot 
contiguous tubes and glasses were even oyverset, nor were 
any of a large audience, and some of them very neat: er 
scratched; but the plank, one and a half inch thick, on wht 
the powder lay, had a hole blown quite through, almost a8 large 
as the palm of one’s hand. This isa striking instance to prove 
that the initial force of this powder, when exploded, is very 
great, but that it extends but a very little way- If it 
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