Compounds. 2OC 



Its weak affinity gives rise to explosive compounds 

 of the utmost importance to man. Gunpowder 1 is 

 not alone for war. It is a great engine of power for 

 the progress of civilization. It not only secures civi- 

 lized society against the inroads of barbarian hordes, 

 by giving greater war power to civilized man, but by 

 its agency he makes his way through the mountains, 

 and overturns the hills by the roots. The works 

 accomplished in our day through the agency of gun- 

 powder are truly marvellous. Gun-cotton, which may 

 be used as a substitute for powder, and the percus- 

 sion-cap that ignites them, are both nitrogen com- 

 pounds. So weak is the affinity of this clement 

 when held in the solid state in combination, that by 

 percussion, or the direct application of heat, its com- 

 pounds are instantly broken up; and this gas, which 

 no mechanical force can compress to a solid, leaps 

 particle from particle, and crushes the solid rocks, 

 or hurls the deadly shot and shell. 



We find this element, then, perfectly fitted for its 

 place in the atmosphere and in organic beings. We 

 see its compounds so essential to living beings, tend- 

 ing to equilibrium, from their distribution in the 

 air or by their formation in it. We find some of its 

 compounds, like nitric acid and the peroxide of ni- 

 trogen, most useful to man in science and art, so 

 corrosive and poisonous, that were they to be formed 

 in abundance, they would destroy all organic life 

 upon the globe. They are simply combinations of 

 that nitrogen and oxygen which float together in the 

 air, and are kept from forming these compounds 



9* 



