AMERICAN HfSTrTTTTE. 489 



^setrth's surface does not, in accordance with tlie nebular theory of 

 La Place, assume permanently the vaporous condition, and take 

 its place between the air and the earth, but for electrical reasons, 

 a-s yet entirely unknown, after ascending into the air it is precipi- 

 tated in the form of drops. The same thing must have occurred 

 during the first geologic period, and from the highly heated con- 

 dition of the earth the oceans of rain which fell escaped imme- 

 diately into the air as steam. One objection that has been urged 

 against granite as a building stone in this city is the fact that it 

 disintegrates and crumbles to powder if water is thrown on it 

 when hot. In regions distant from the sea $hore thrifty house- 

 wives use the erratic boulders for obtaining sand by heating them, 

 and then suddenly cooling them by the affusion of water. When 

 the earth became cool enough to allow water to exist on the sur- 

 face in the form of oceans, they were extensive boiling cauldrons, 

 giving rise to immense quantities of rain, that falling on the dry, 

 hot rocks, still further disintegrated them, and washed the sand 

 down to the ocean, as bare hills and mountains are now washed, 

 only to thousands of times greater extent. In these seething 

 oceans were formed the first stratified rocks, while the water was 

 yet too hot to allow of organic life, and hence no fossils are found 

 in them. 



But the rain and sun shine though circumstances which govern 

 the distribution of plants are only conditions to which all plants 

 are subject — conditions which affect them only as exercise affects 

 animals, by increasing or decreasing the amount of food which 

 they may appropriate. There are two or three other conditions 

 of the same sort, such as in the soil a, proper degree of fineness 

 together with a certain degree of humus and of clayj also a defi- 

 nite quantity of carbonate of ammonia. But these conditions, 

 however strenuously we may insist on them in the practice of 

 agriculturer, are always present like rain or sunshine, to a 

 greater or less extent, and are only to be regarded as means of 

 assimilating the true food of the plant — the inorganic matters it 

 derives from the soil. 



To that doctrine of Liebig that regards the mineral ingredients 

 of plants as the basis of a definite chemical organization, it has 



