204 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1932 



permutite the calcium is removed by substitution for the sodium and 

 the water is thus softened. When all the sodium is eventually re- 

 placed, the filter ceases to soften the water. The permutite is then 

 regenerated by running a concentrated solution of NaCl through the 

 filter, which is then ready to soften more water. These reactions take 

 place according to chemical equivalents and the law of mass action. 

 Ganssen has shown that the so-called soil zeolites present in soils 

 are identical with the permutites. By erosion the materials of the 

 soils are carried to the ocean. Here they come in contact with what 

 is essentially a strong solution of NaCl and the opportunity for base 

 exchange is afforded. Eventually they settle out and become consol- 

 idated to form the sedimentary rocks. 



From these considerations it follows that much of the sodium in 

 shales is probably of adsorptional and base-exchange origin. There- 

 fore, since shales make up 50 per cent of the sedimentary rocks and 

 sedimentary rocks cover three-fourths of the globe, much of the 

 river-borne sodium has already been in the ocean ; it also is cyclic 

 sodium. From Stremme's comparison of fresh-water with marine 

 clays it appears that one-half of the sodium in the shales may be 

 due to adsorption and base exchange. Stremme's interesting results, 

 however, need confirmation. 



Some salt has been removed from the ocean by the deposition of 

 the salt beds that occur in the geologic column from Cambrian time 

 onward. Although these deposits are vast in quantity (3 X 10^^ tons 

 being estimated by Darton for the salt in the Permian beds of the 

 American mid-continent region alone), yet they are negligible in 

 comparison with the total amount in the ocean (4.1X10^'^ tons). 



Although, then, the loss of sodium by precipitation to form salt 

 beds has been negligible, yet the loss by adsorption and base ex- 

 change appears to have been sufficiently large to vitiate computations 

 on the age of the ocean, especially in the precise forms given these 

 computations by Joly and Clarke. The problem of the age of the 

 ocean by sodium accumulation is not the validity of corrections of a 

 few per cent to the estimate of 100,000,000 years, but of whole orders 

 of magnitude. 



Other sources of sodium chloride in river water are: (1) Human 

 contamination; (2) salt in the sedimentary rocks, which has been 

 entrapped in them at the time they were formed on the floor of the 

 ocean; and (3) the gases emitted from volcanoes during eruptive 

 activity. Of these sources only the volcanic emanations are pos- 

 sibly new contributions to the ocean. Chlorides are freely emitted 

 at certain volcanoes, chiefly hydrochloric acid, though the chlorides 

 of sodium and potassium are abundant. Vesuvius, for example, is 

 often covered after an eruption with a white mantle of chlorides of 



