SECT. i. CARBON. 13 



poisonous, those with oxygen are all deadly poisonous. 

 Had nitrogen combined spontaneously with either of 

 these gases, especially with oxygen, life would have been 

 impossible as the organized creation is constituted ; its 

 inertness renders its mixture with oxygen in atmospheric 

 air innocuous. However, combinations of nitrogen^and 

 hydrogen, forming nitrate of ammonia, have been dis- 

 covered in the atmosphere by Professor Schonbein, the 

 union of evaporation, heat and air being the cause ; and 

 as evaporation is continually going on, he concludes 

 that nitrate of ammonia, nitrates and other salts are 

 generated in the moist air, and are speedily washed 

 down in our rainy climates into the springs and rivers. 

 He considers the formation of nitrates out of water as 

 highly important for vegetation, because each plant 

 becomes a generator of a portion at least of its azotized 

 food, while the rain furnishes the ground on which it 

 stands with a supply of the same. 



In the atmosphere, nitrogen has all the mechanical 

 properties of common air, but with a greater refractive 

 power, and its specific gravity is nearly the same with 

 that of oxygen. Since the atmospheric gases are the 

 most permeable to radiant heat, the earth is in the 

 most ftivourable circumstances for being warmed by the 

 solar rays, and thus the properties of the elementary 

 gases are admirably adapted for our comfort, nourish- 

 ment, safety, and pleasure. 



Carbon, which combined with the three elementary 

 gases forms the basis of the organic creation, is widely 

 distributed throughout the globe, in enormous coal~ 

 formations, the vegetation of former ages. Diamond is 

 its purest crystalline form ; and charcoal, which is wood 

 whence the volatile matters have been driven off by heat, 

 is its purest amorphous state. To this simple substance 

 and to hydrogen, we are indebted for terrestrial light 

 and heat, whether our fuel be coal or wood, our light a 



