January joth, I po6.'\ PROCEEDINGS. xi 



a solution of chlorides and sulphates, in which calcium, and 

 perhaps magnesium, would probably preponderate as bases. 

 Much silica would also enter into solution, to be afterwards 

 deposited in the crystalline form. Insoluble or slightly soluble 

 sulphates such as those of barium and calcium, would also 

 sooner or later separate out. The atmosphere would still contain 

 a large amount of carbon dioxide, and the gradual decomposition 

 of the exposed parts of the earth's crust by the moisture and 

 carbon dioxide would result in the dissolving out of the alkalies 

 as carbonates, which would be carried into the sea. The 

 immense amount of calcium which existed in the primitive ocean 

 has since been removed by the agency of organisms of various 

 kinds, and now exists as calcium carbonate, in the form of lime- 

 stone chalk, coral, &c. The place of the calcium in the water 

 would thus gradually be taken by the sodium carried down by 

 the rivers. 



David Forbes objected strongly to Sterry Hunt's views, and 

 an animated and finally somewhat acrid controversy took place. 

 Forbes contended that, in the cooling globe, the chlorine would 

 unite with sodium in preference to hydrogen, and thus common 

 salt would be deposited all over the globe long before the water 

 became liquid, Forbes said that there would be a layer of salt 

 lo feet thick all over the globe, which would be immediately 

 dissolved when the water condensed, so that, according to him, 

 the sea would be salt from the very beginning. (Forbes' cal- 

 culation was lamentably wrong ; Joly has since calculated that 

 there is enough salt in the sea to form a layer 112 feet thick 

 over the whole globe.) 



Probably no modern chemist would accept Forbes' view. 

 The temperature at which common salt would solidify would be 

 quite high enough for silica and silicates, in conjunction with 

 water vapour, of which there would be an immense amount, to 

 decompose it, and this of course would result in the liberation 

 of hydrochloric acid. Further, authorities are pretty well agreed 

 that there is nearly as much potassium as there is sodium in the 

 earth's crust, and as the heat of combination of chlorine with 



