26 Proceedings of the Royal Physical Society. 



tenet of the geologist with reference to inanimate nature, 

 viz., that the processes we see in operation around us are 

 those which have been in operation throughout past ages, 

 and are those which will be operative in the future, is 

 equally applicable to the organic world, including Man. 



I am therefore drawn to conclude with the words of Omar 

 Khayyam, who may have had glimmerings of the theory of 

 Evolution when he said — 



"With Earth's first Clay They did the Last Man knead. 

 And there, of the Last Harvest sow'd. the Seed ; 

 And the first Morning of Creation wrote 

 What the Last Dawn of Reckoning shall read." 



— Hiibdiydt, stanza 73. 



I. The Origin of Bock-Salt. By J. G. Goodchild, of the 

 Geological Survey, F.G.S., F.Z.S. 



(Read on December 19, 1894, and recommitted January 15, 1902.) 



In discussing the mode of origin of Kock-Salt, many ques- 

 tions present themselves for consideration. For instance, if 

 we wish to discuss the origin of the saltness of the sea, it is not 

 sufficient to assume, as many have done, that the chloride 

 of sodium in sea-water has been derived from the land : 

 we have rather to inquire whether it may not be an original 

 feature. In making that inquiry, we are led to consider the 

 earlier stages of the history of the Earth ; and we are 

 finally led back to the consideration not only of that, 

 but also of the history of the Solar System as a whole. 

 In regard to this latter point, it is probably the case that 

 most cosmogonists are now agreed that the theory which 

 seems best to harmonise the greatest number of known 

 facts, is that which is based upon the assumption that 

 the whole of the Solar System has consolidated from an 

 original nebulous state. It is capable of proof that the 

 incandescent gases which formed the primeval nebula 

 consisted of elementary bodies identical with those which 

 enter into the composition of our Earth and its sister 

 planets. It is, of course, also capable of proof that these 

 constituents were raised to the state of incandescent vapour 



