EVOLUTION 169 



geological era, silicides, carbides, phosphides, and nitrides 

 were formed in stable combinations instead of the oxides, 

 silicates, carbonates, phosphates, and nitrates of the present 

 time. These combinations existed on the earth at a time 

 when the conditions of temperature precluded the existence 

 of water in a liquid state. As the temperature cooled, and 

 the water vapour became condensed, it entered into chemical 

 combination with the various rocks, producing organic com- 

 pounds like acetylene, which results from the action of water 

 on calcium carbide. H. Lenicque has developed a theory as 

 to the formation of various rocks under these conditions, 

 which he communicated in 1903 to the French Society of 

 Civil Engineers. 



The chemical evolution of the globe has undergone great 

 changes as the temperature gradually fell and the constitution 

 of its crust altered. As long as the temperature was higher 

 than that at which water can exist, all chemical reactions 

 must have taken place between anhydric substances, elements 

 and salts in a state of fusion. These conditions are very 

 different from those of the present-day chemistry, which is the 

 chemistry of aqueous solutions. We may hope to be able to 

 reproduce the earlier conditions by the experimental study of 

 anhydric substances in a state of fusion. 



At a later period, that of the primary and secondary rocks, 

 there was a uniform and constant temperature of about 40° C. 

 The atmosphere was charged with water vapour, and all the 

 conditions were present for the production of storms and 

 tempests. The atmosphere during long ages must have been 

 the seat of formidable and incessant electric discharges: these 

 discharges are the most powerful of all physical agents of 

 chemical synthesis, and will cause nitrogen to combine directly 

 to form various compounds -nitrates, cyanides, and ammonia. 

 Carbonic acid would also be present in abundance and would 

 enter into combination with these nitrogenous compounds. 

 In this way we may imagine that compounds were formed 

 which by some process of physical synthesis subsequently gave 

 rise to vast quantities of albuminoid matter. At that time 

 the seas and oceans contained all those substances which have 



