APPENDIX YI. 



CALCULATION OF THE AGE OF THE EARTH FROM THE 



MEASUREMENT OF THE DRAINAGE OF SODIUM FROM 



THE LAND INTO THE SEA. 



JoLY has attempted to estimate the age of the ocean from a knowledge 

 of the amount of sodium in the sea, and the amount which annually 

 enters it from the land. He finds from Murray's tables that the 

 amount of sodium annually entering the sea is about 157,270,000 tons, 

 and that the amount contained in all the oceans of the world is about 

 14,151,000,000,000,000 tons. Therefore the age of the ocean is 

 apparently about 90,000,000 years. But Joly assumes that Ihe first 

 oceans due to the condensation of water vapour from the primitive 

 atmosphere contained about 14:7o of the sodium now present in the 

 seas. On the other hand the amount of sodium in the sea is 

 probably higher than is shewn in Murray's tables : Joly puts it as 

 15,627,000,000,000,000 tons. Again 10 7, of the sodium entering the 

 sea from the land comes from the former in evaporated water and is 

 simply returned to the sea — not dissolved from out of the rocks. These 

 corrections indicate that the more probable age of the ocean is about 

 89,300,000 years. 



The Rev. O. Fisher criticises this estimate, pointing out that salt is 

 probably imprisoned in the sedimentary rocks and is again returned to 

 the sea on the weathering of the latter. This pre-indicates a circulation 

 of salt to and from the sea. The efiect of this correction is to 

 multiply Joly's estimate several times. 



Dubois also points out that the amount of salt dissolved out from the 

 rocks is only about one-quarter of that deduced by Murray. If this 

 is the case then Joly's estimated age must be quadrupled. 



The literature of these calculations is summarised in a paper by 

 Macallum in Trans. Canadian Institute, Vol. vii. Pt. 3, p. 536, 1904. 



