446 



Scientific Proceedings, Royal Dublin Society. 



tlie standard curve. For the 1 

 Day and E. B. Sosman of the 



ithinm silicate I am indebted to Messrs. A. L. 

 Greophysioal Laboratory at Washington : — 



w 



300 500 



900 1100 



1500 I'OO 



Fig. S. Degrees Centigrade. 



