39 



occupied by it, there really exists a something, binding 

 the sun and the planets in a common whole. Research 

 will also lead us to the further assumption that this 

 something is oxygen, united with hydrogen gas. 



Our air consists of four elements: hydrogen, oxygen, 

 nitrogen and carbon. Hydrogen in a pure state is no- 

 where found in nature, it is found always in combination 

 with oxygen or some other matter. Carbon is a heavy 

 gas and sinks always if we may so speak, to the bottom 

 of atmospherical spaces. Nitrogen is also a heavy gas, 

 and it presses round the earth, by comparison with the 

 other gases, in enormously preponderant mass. Oxygen 

 and especially hydrogen are very light gases ; at any 

 rate much lighter than the air, and they posses the fol- 

 lowing qualities. Oxygen, oxidising as far as possible 

 all nature's elements, changes their original forms, con- 

 verting them into bodies so widely unlike that it is 

 difficult to discern by any outward sign that the trans- 

 formed matter so much as contains its original elements. 

 In order to reveal these elements it is necessary to re- 

 sort to chemical analysis. Hydrogen, although in certain 

 cases it unites with solid and liquid bodies, not- the less, 

 does so less frequently : it acts however as a rousing 

 principle throughout nature. 



The most interesting question is now to determine 

 how the atmosphere which surrounds the earth is formed. 

 A naturally pure atmosphere presents about 8 parts of 

 hydrogen, 16 parts of oxygen, 76 parts of nitrogen and 

 1 / of carbon. Carbon is expired in animal breathing ; 

 it is a gas highly injurious to animal organisms, but 

 exists in large quantities in various combinations. Peat- 

 lands, lime-pits, coal-mines, bogs, decomposing vegetable 

 masses, animal fats furnish it in abundance. Were it not 

 a heavy gas, were it able to free itself from organic com- 

 binations and rise in the air, animal life on earth would 

 be unthinkable. Not the less a certain percentage of it 

 constitutes an essential and indispensable element in the 

 earth's atmosphere. 



