168 Cautions, ^c. respecting Fulminating Powders. 



section of the union, a State legislature may thus provide for 

 the protection of capital, engaged in enterprise of uncommon 

 risk, as well as of uncommon usefulness, without excluding 

 other and better inventions, should they arise. 



I shall ask leave to communicate, for some future Number, 

 the results of experiments, now making, with the gas fire 

 applied to engines. 



I am your most respectful humble servant, 



• ■ JOHN L. SULLIVAN 



Art. XVI. Cautions regarding Fulminating Powders. 

 Fulminating Mercury. 



X-^URING a late lecture in the laboratory of Yale College, a 

 quantity of fulminating mercury, probably about 100 or 150 

 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 oyer the 

 powder, as a guard, but without touching jt, and stool and all 

 stood on one of the shelves of the pneumatic cistern, sur- 

 rounded by tall tubes and other glasses, several of which 

 were within 6 or 8 inches. A small quantity of the fulmi- 

 nating powder, at the distance of a few feet, was merely 

 flashed, by a coal of fire, but without explosion. In a man- 

 ner, not easily understood, the whole quantity of powder 

 under the large glass instantly exploded with an astounding 

 report ; but the glass was not exploded — it was merely thrown 

 up a little ; in its fall it was shattered, and broke a glass which 

 it hit, but no fragment was projected, and none of the other 

 contiguous tubes and glasses were even overset, nor were any 

 of a large audience, and some of them very near, even 

 scratched ; but the plank, one and a half inch thick, on which 

 the powder lay, had a hole blown quite through, almost as large 

 as the palm of one^s hand. This is a 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 be 



