78 KANSAS CITY REVIEW OF SCIENCE. 



its liquefaction; or else, the atmosphere being so constituted as to permit vital 

 processes, that carbonic di-oxyd, as fast as removed by chemical action at the 

 earth's surface, was supplied from some extra-terrestrial source. We may, in 

 accordance with this last hypothesis, admit that the atmosphere is not terrestrial 

 but cosmical, and that the air, together with the water surrounding our globe 

 (whether in a liquid or a vaporous state), belongs to a common elastic medium 

 which, extending throughout the interstellary space, is condensed around attract- 

 ing bodies in amounts proportional to their mass and temperature, etc. " If this 

 view be correct, it would follow that the diffusion of gases would maintain a cer- 

 tain equilibrium between the atmospheres of different centers of attraction through- 

 out space.- This view was first advanced by Sir William R. Grove, in 1842, re- 

 newed in 1866, and mentioned by many others since. According to this theory 

 our moon should have an atmosphere; but astronomers have failed to detect it. 

 There can be no doubt that carbon di-oxide was much more plentiful in the air 

 in early times than it now is. The wonderful growth of vegetation can only be 

 accounted for in this way. It is also the most probable cause of the warm tem- 

 perature of early times. Tyndall very beautifully showed that a small addition of 

 this gas to the air would greatly elevate the temperature by preventing the radia- 

 tion of heat from the earth, just as the "cold frame" does which the gardener 

 uses in early spring. But to return from this digression. As before stated, the 

 action of the acid liquid on the primitive crust would furnish abundant material 

 for sedimentary deposits. Feldspars disintegrated furnish clays. Almost any 

 sihcate that would be affected by acid, would furnish sediments. The crust was 

 probably a mechanical mixture to a great extent, so that quantities of it which 

 were unaffected by the acids, were left in a finely divided state. It is difficult to 

 conceive of the waters under such conditions as being at rest. The tossing ocean 

 that was just being formed would have been an ample vehicle for these sediments, 

 so that deposits could have been formed before dry land emerged. We may look 

 mostly to the air and water for causes of the various phenomena since dry land 

 appeared. That organic matter, resulting from both animal and vegetable life, 

 has also played an important part in geological phenomena is now well known. 



The ocean waters would hold in solution great quantities of soluble salts, 

 particularly chlorides of sodium, calcium and magnesium, and sulphates of so- 

 dium and magnesium. Rain water washes from the air large quantities of carbon 

 di-oxide, free oxygen, some ammonia, also organic impurities which have been 

 reduced to a finely divided state and are held in the air. By coming in contact 

 with decom, osing vegetation the water becomes charged with organic matter 

 which soon combines with the free oxygen, forming thereby more carbon di-oxide. 

 This changes the water from an oxidizing to a reducing agent. Sulphides owe 

 their existence to this fact. Some sulphates are reduced directly to sulphides by 

 giving up their oxygen to carbonaceous matter held in solution. Others are re- 

 duced in such a manner that sulphydric acid is generated. This being very solu- 

 ble in water may be carried by it to different places. It is thus brought in con- 



