118 THE CANADIAN NATURALIST. [Dec. 



acid liquid, which, attacking the crust of the silicates, separated 

 vast amounts of silica, and became saturated with earths and 

 alkalies, forming the primeval sea. This condition of things, he 

 claimed, was in strict accordance with the known chemical laws, 

 and flowed logically from the hypothesis of the origin of our 

 planet. The early ocean should thus have abounded in salts of lime 

 and magnesia ; and this is confirmed by the saline waters from the 

 Paleozoic rocks, which represent fossil sea-water of that ancient 

 period. Dr. Hunt here referred to his extended chemical and 

 physical investigations of the older rocks, and their mineral 

 springs, in support of this view. 



The stronger acids of chlorine and sulphur having been 

 separated from the atmosphere, a decomposition of the silicates of 

 the exposed portion of the earth's crust, under the influence of 

 carbonic acid, moisture, and heat, went on, resulting like the 

 modern process of kaolinization, in the production of a silicate of 

 alumina or clay, and carbonates of the protoxyd bases. In this 

 way great quantities of carbonate of soda were formed, which, 

 decomposing the lime and magnesia salts of the sea, gave rise 

 to the first limestones, and to chlorid of sodium. Hence the clays, 

 the limestones, and the sea-salt were the joint results of a process 

 which was slowly removing from the earth its carbonic acid, 

 and fitting it for the support of higher forms of life. These 

 views of Dr. Hunt, first put forward in 1858 and 1859, are 

 gradually being received and appropriated by writers, who do not 

 always acknowledge the source of them. They are here insisted 

 upon as preliminary to some considerations on the atmosphere of 

 early times, when it must have contained, in the form of carbonic 

 acid, the whole, or the greater part of the carbon now present in 

 the strata of the earth, and in bodies of fossil coal. 



Simple calculation show that the carbonic acid contained in a 

 layer of pure carbonate of lime extending over the earth, with a 

 thickness of 8-61 meters, would, if set free, double the weight of 

 our atmosphere ; and that from 13-65 meters, (about forty-four 

 feet), would double its volume. It moreover appears that a 

 similar layer of ordinary coal, one meter in thickness, would suffice 

 to convert into carbonic acid the whole of the oxygen of the 

 atmosphere : so that if, as is probable, the whole amount of coal 

 and carbonaceous matters on the earth exceeds this quantity, 

 there must have been an absorption of the oxygen, set free during 

 the conversion of carbonic acid into coal, this oxygen being 



