A CORRECTION 



CHARLES R. VAN HISE 

 University of Wisconsin 



In Monograph 47 of the United States Geological Survey, A 

 Treatise on Metamorphism, a serious mistake is made in reference 

 to the redistribution of sodium. It is stated on p. 997 that the defi- 

 ciency of soda in the sediments as compared with the original rocks 

 is 2.4985 per cent., and that this deficiency amounts to 70.38 per 

 cent, of the whole. In estimating the deficiency in metric tons for 

 the soda, the computor, instead of using the amount of soda in the 

 original rocks as the base, took the weight of the entire mass of 

 sediments, and thus the deficiency of soda is given as 475,065,000,- 

 000,000,000 metric tons, whereas it should be 16,864,875,000,000,000 

 metric tons. The total amount of soda in the ocean, 19,101,000,- 

 000,000,000 metric tons, instead of being but a small fraction of the 

 total deficiency for the sediments, is 13.2 per cent, in excess of the 

 deficiency. 



This error requires the modification of a number of statements 

 made on p. 998. It is there stated that the result obtained suggests 

 that the soda of the salt deposits of the land is probably greater in 

 amount than in the salt of the sea, whereas the true result indicates 

 that the soda of the salt deposits of the land is unimportant as com- 

 pared with that in the sea. Also a criticism in reference to calcu- 

 lating the age of the earth from the amount of salt in the sea is without 

 force. 



No adequate excuse for the error in calculation can be offered; 

 it can only be said that it occurred. In the Treatise on Metamor- 

 phism there are the results of thousands of numerical calculations. 

 In the one cited a blunder was overlooked. We hope that for the 

 most part the calculations will be found substantially correct. 



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