154 PROCEEDINGS OF THE AxMERICAN ACADEMY. 



101.17» 



1 Including Li20. 



2 Total No. 5 and probably 8-9-10 are loss on ignition. 



^ The total is too high, a fault most difficult to avoid in the laboratory 

 where it was made. In the summer when the windows have to be open the 

 dust from innumerable trains and the street causes small increments, chiefly 

 silica, to accumulate. — C. H. W. 



* ZrOs. 



No. 1. Riebeckite, from pegmatite, Fallon Quarry, North Common Hill, 

 Quincy, Mass., U. S. A. Analysis by Warren. 



2. Riebeckite, Island of Socotra. Analysis by Sauer, Z. D. G. G., 40, 



138 (1888). 



3. Riebeckite, Island of Socotra. Analysis by Sauer, ibid. 



4. Riebeckite, Colorado, U. S. A. Analysis by Koenig, Zs. Kr., 1, 430 



(1877). 



5. Riebeckite, Cape Ann, Massachusetts, U. S. A. Analysis by Dr. J. F. 



McGregory. Quoted by Rosenbusch, Mikr. Phys., p. 341, from 

 private correspondence. 



6. Riebeckite, Red Hill, New Hampshire, U. S. A. From Paisanite, 



Pirsson and Washington, Am. J. Sci., 33, 439 (1907). Calculated 

 from the rock analysis. 



7. Crocidolite, South Africa. Analysis by DoeUer, Zs. Kr., 4, 40 (1879). 



8. Crocidolite, South Africa. Anah'sis by Renard and Klement, Bull. 



Ac. Belg., 8, 530. 



9. Crocidolite, Cumberland, Rhode Island, U. S. A, Analysis by Chester 



and Cairns, Am. J. Sci., 34, 108 (1887). 

 10. The Same as No. 8. 



