1902-3.] The Pal^ochemistry of the Ocean. 54 



combination of the dissociated elements and the condensation of the 

 compounds formed from them possible at a much higher temperature.* 



At such a temperature the previously molten rock had become 

 rigid, and of course the condensed compounds would be deposited on 

 its surface, and when refusion of the rockcrust occurred, as it must 

 have done over large areas, large quantities of the deposited compounds 

 would be diffused through the superficial crust. When the cooling of 

 the atmosphere and globe progressed until the temperature of the former 

 was 370°C, the first condensation of water took place on the rock 

 surface. The atmospheric pressure, according to Joly,f must have been 

 about 270 times what it is now. According to Clarke's J estimate of the 

 relative values of water and carbon dioxide to that of the solid portion of 

 the globe, the atmospheric pressure before the first condensation took 

 place, was about 247 times what it is at present. Joly affirms that at 

 370°C a pressure of 190 atmospheres would produce a condensation of 

 water, and, as the pressure was much higher, condensation would go on 

 till the pressure fell below 190 atmospheres. This would entail rapid 

 evaporation, for at many points the temperature of the rock surface 

 would be so high that the water would condense only to boil away 

 immediately. This would collect the salts deposited on the surface in 

 masses, and it would, as in the case of the chlorides of magnesium, iron 

 and aluminium, convert these into oxides of these metals and free 

 chlorine, which, uniting with hydrogen, would form free hydrochloric 

 acid. The other chlorides, namely, those of sodium, potassium and 

 calcium would be unaffected. The ferric chloride would in some cases 

 be volatilized but to be recondensed. 



This condensation of the water vapour, and the re-evaporation would 

 occur a countless number of times before there would obtain a perman- 

 ent body of water on the globe. Where such first occurred there would 

 be a lower temperature than elsewhere, and in consequence further 

 condensation of water vapour would occur there also. The result would 

 be the first ocean basin, the weight of the body of water acting on the 



* The volatilization points of potassium, sodium and magesium are 667°C, 742°C, and i ioo°C respec- 

 tively. The meltingf points of calcium and aluminium are unknown. The melting pomts of certain sodium 

 and potassium compounds are, according to V. Meyer & Riddle (Ber, d. d. Chem. Gesell. Vol. 27, 

 p. 2,443,) as follows: 



NaCl 8si°C. I KCl 766X. 



NaBr l^fC. K Br 71SX. 



Na I 6so°C. K I eas'C. 



Na2 CO3 ...logS'C. K2 CO3 io4S°C. 



Naa SO4 843''C. | K 2SO4 io73°C. 



t op. cit. 



t F. W. Clarke, The Relative Abundance of the Chemical Elements. Bulletin U. S. Geol. Survey 

 No. 78, i8gi. 



