44 



English service powder may be taken as in a loo parts : — 

 Nitre 75 parts, Charcoal 15 parts, Sulphur 10 parts. 



But these substances retain their individuality in Gun- 

 powder, being simply intimately mixed like the ingredients 

 in a pudding. 



This I can shew by treating a sample of powder with 

 boiling water, when all the nitre is extracted by it, and on 

 filtering and boiling off the water we shall obtain at the 

 end of the lecture a crop of crystals of nitre. The residue 

 containing the charcoal and sulphur is now treated with 

 bisulphide of carbon which dissolves the sulphur only, 

 and on evaporating off the carbon bisulphide, crystals of 

 sulphur are deposited. The residue of the powder now 

 consists of charcoal only, and, of course, is non-explosive. 



On the perfect incorporation of the ingredients of Pow- 

 der, its utility entirely depends, and although time will not 

 allow me to describe the preparation of military powder, it 

 will suffice to say that it is incorporated thoroughly with 

 water, the paste so formed pressed, dried, broken into 

 lumps, divided by sieving into fragments of the desired 

 size, and these lumps or grains "faced or glazed" with 

 black lead. All these processes are carried on with the 

 gi^eatest care and regularity, and their importance is well 

 seen if I lay two trains of equal length of powders of the 

 same composition (i) being Military Powder, (ii) a powder 

 made by me with great care but without any of the special 

 appliances necessary. Firing these trains at the same 

 moment, it is seen that whilst the MiHtary powder fires 

 with the greatest rapidity and leaves little or no residue, 

 the home-made powder burns slowly and irregularly, and 

 leaves a large amount of solid residue. 



The question naturally occurs — Why are three in- 

 gredients used ? In answer, the two essential are the nitre 

 and charcoal. The nitre represents condensed oxygen (one 

 cubic inch of solid nitre containing as much available oxygen 

 as 3,000 cubic inches of air), and on explosion, the carbon of 

 the charcoal acts on the nitre, and gaseous products are 



