936 



A TREATISE ON METAMORPHISM. 



Symbols, atomic weights, a and jiroportions of the twenty-thre 

 in the outer 10 miles of the earth.. h 



most abundant elements 



"In Chapter V, page 193, the list of atomic weights is given on the basis of hydrogen as 1. The 

 table of rock-making minerals is also constructed on this basis. However, so far as the results of 

 increase and decrease in volume of the minerals are concerned, it makes no difference whether 

 hydrogen be taken as 1 and oxygen as 15.88, or whether oxygen be taken as 16 and hydrogen as 1.01. 

 As the more common practice of the chemists is to use oxygen as 16, the table of atomic weights here 

 given is on that basis. See Wiechmann, F. G., Atomic weights: Science, vol. 9, 1899, p. 23. 



6 Clarke, F. W., Beport of work done in the Division of Chemistry and Physics, 1889-90: Bull. 

 U. S. Geol. Survey No. 78, 1891, p. 39. Clarke, F. W., Analyses of rocks, laboratory of the U. S. 

 Geological Survey, 1880-1899: Bull. U. S. Geol. Survey No. 168, 1900, p. 15. 



c With bromine. 



