chloride of sodium or common salt. It has been calculated that 

 there is sufficient salt to cover the entire sphere with a coating 

 some ten feet in thickness. 



The next lowering of temperature would condense the vapour 

 of water and carry it down as rain, and which, by dissolving the 

 chloride of sodium and other soluble chlorides, would make the 

 ocean salt from its first commencement. 



The atmosphere, with the exception of the presence of a great 

 excess of carbon in the shape of carbonic acid, would then be as it 

 is to this day, a mechanical mixture of oxygen and nitrogen, and 

 it may not be out of place to remark here in passing that we hare 

 from this time in the atmosphere the very four elements, and only 

 those, viz., carbon, oxygen, nitrogen, and hydrogen (the hydrogen 

 being in combination with oxygen, and forming vapour of water), 

 that make up the protoplasm, from which, according to Professor 

 Huxley and his school, all life has sprung. 



The carbonic acid would render the air unfit to sustain the life 

 of the higher forms of air-breathing creatures, and it was not until 

 the carbon had been stored up by a Ivixurious vegetation, as 

 represented in the coal measures, that the way was paved for their 

 appearance. 



" As the crust was being formed, further cooling would cause it 

 to crack and become fissured, and the molten matter beneath 

 rushing through the fissures would give rise to depressions and 

 elevations, forming the first mountains and valleys, and these by 

 giving direction to the water in the ocean and rivers, would 

 determine the earlier sedimentary formations." * 



From this time the changes that have taken place in our globe 

 which is to this day gradually cooling and suffering contraction, 

 were effected by agencies, similar, if not identical, with those now 

 in operation, and to gain any proper idea of the formations which 

 have resulted from the disintegration of the earth's primitive crust, 

 we must not only take into account the agency of fire and water, 

 but the various effects produced by chemical action and mechanical 

 force. 



• David Forbes, F.E.S. 



