MISCELLANEOUS HINTS. 411 



combustion of the grains and to the rapid transmission of the 

 flame through the whole mass of the powder."* 



TESTS FOR POWDER. 



English sporting-powder, when good, is found to impart scarcely 

 any color to the hand when crushed in the palm with the thumb. 

 American powder, to be perfect, should be equally free from all 

 charcoal appearances. There is a simple method of ascertaining 

 the quality of powder, which in some measure may be relied on. 

 If a small quantity be placed upon a sheet of white paper and 

 exploded, it should burn with a sudden white smoke, accompanied 

 with a peculiar sharp report, or rather phiz, that the ear soon be- 

 comes familiar with and easily detects. There should be nothing 

 left on the paper after the explosion if the powder be superior ; if, 

 however, the residuum be blackish matter, the probability is that 

 there is too much carbon in the powder ; if the paper should 

 exhibit a dotted appearance, with little black splotches over it, we 

 would be led to suppose that the sulphur or nitre was inferior in 

 quality and badly incorporated. 



. THE EPREUVETTE, OR POWDER-PROVER. 



It is not an easy matter to ascertain the real pulsion of powder, 

 even by subjecting it to the test of the epreuvette, an instrument 



* See report of experiments on gunpowder, made at Washington Arsenal by Cap- 

 tain Mordecai. 



