NO. 6 AGE OF THE EARTH — BECKER 9 



siliceous rocks. Its gradual decomposition might yield chlorine, and no 

 other equally probahle origin for the chlorine of volcanoes or deep springs 

 is known. 



Assuming that the supjily of juvenile chlorine not combined with 

 sodium is sufficient to maintain the present ratio of chlorine to bases in 

 the ocean, it is possible to account for a part of the river-borne sodium 

 chloride. Of the volcanic chlorine substantially 3/4 must fall into the sea 

 and if this were exactly equivalent to the unchloridized river sodium, the 

 volcanic chlorine precipitated on the continental areas would suffice to 

 chloridize one-third as much sodium as escapes chloridation until it 

 reaches the ocean. Furthermore, in the present ocean there is about one 

 and a seventh times as much chlorine as is needed to combine with oceanic 

 sodium. On the hypothesis suggested this should also be the case on land. 

 Thus if the unchloridized river sodium is 62.57 X 10" tons, the volcanic 

 chlorine should be equivalent to the following amount of sodium : 



yX 3 X62.57xl0«^95 X]0« tons 



The chlorine equivalent of this sodium equally distributed over the 

 earth's surface and dissolved in a rainfall of B. meters would give a normal 

 chlorine content 



^_ 0^864 



so that if the rainfall were one meter, the normal chlorine content at 

 inland stations would be less than 3/10 of one part per million. It is to 

 be desired that analyses of the rainfall should be made at a well dis- 

 tributed set of stations for many purposes, one of them being to ascertain 

 what is the normal chlorine of the rainfall. This, however, may vary from 

 year to year. 



The total river-borne sodium less 6 per cent, for cyclic sodium is 

 164.5 X lO'' tons. About 2 per cent, of this amount is covered by the 

 chlorine of the rocks and, according to the hypothesis of volcanic chlorine 

 set forth above, 95 X 10" tons more is thus accounted for. The sum of 

 the two items amounts to over 98 X 10" tons, but leaves no less than 

 66 X 10" tons of river-borne sodium, or 40 per cent, of the total, which is 

 chloridized but the chlorine of which has not yet been traced. 



There is no doubt that a part of this sodium chloride is juvenile and 

 that another portion is what may be called secular. Sediments at their 

 first emergence from the ocean are saturated with salt water and any 

 porous rocks, particularly sandstones, if temporarily submerged are 

 recharged with salt water. Well compacted sands contain approximately 

 20 per cent, of interstitial space, and it is easy to compute that the whole 

 mass of sandstones must originally have contained highly important 



