102 Allen and Clement — Bole of Water in Tremolite. 



ordinary. These efforts also proving unsuccessful, the idea 

 suggested itself that the mineral was perhaps hydrous and 

 therefore must be made by the agency of water, in spite of 

 the general opinion among mineralogists that tremolite is 

 anhydrous. 



.Material for Study. — In order to establish the true compo- 

 sition of tremolite, we made a careful selection of specimens 

 from five different sources. The color of the specimens indi- 

 cated that they contained very little iron and the microscopic 

 examination showed them quite free from inclusions, though 

 some of them required separation from comparatively coarse 

 grains of other minerals intergrown with or adhering to them. 

 This was done with heavy solutions, either potassium mercuric 

 iodide, or mixtures of methylene iodide and benzene. After 

 it had been ascertained by the microscope that each specimen 

 was as pure as it was practicable to get it, it was carefully ana- 

 lyzed. The results are given in Table I. An inspection of 

 the five analyses (I-V) shows that water* is present in all of 

 them and ranges from 1-72-2-50 per cent, averaging 2* 17 per cent 

 in the two purest specimens. It may therefore be regarded as 



Table I. — Analyses of Natural Tremolites. 









Localities 









1 



2 



3 



4 



5 



6f 



n 



Hani 



Ossin- 



Gouver- 



Rus- 



Ed- 



Eich- 





Island, 



ing, 



neur, 



sell, 



wards, 



ville, 



Lee, 



Alaska 



N. Y. 



N.Y. 



N. Y. 



N. Y. 



N. Y. 



Mass. 



Si0 58-59 



57-35 



56-92 



56'36 



58*24 



57-45 



57 69 



TiO, 



•07 



•10 



•06 



•04 





•14 



Al 2 3 -._ -10 



1-21 



1-65 



1-88 



•60 



1-30 



1-80 



Fe.O, .. .. 



•11 



•36 



•61 



•43 



•18 



none 



FeO.-__ .. 



•23 



none 



1-01 



none 



•22 



"55 



MnO... _. 



•01 



__ 



•04 



1-28 



•07 



trace 



MgO... 24-78 



23-87 



23-81 



22-97 



25-16 



24-85 



24-12 



CaO 13-95 



14-02 



12-51 



12-82 



10'85 



12-89 



13-19 



Na 2 0... -12 



•42 



1-22 



•94 



82 



•67 



•4 8 



K 0.... -10 



•19 



•60 



•74 



•10 



•54 



•22 



H 2 0.--. 2-81 



2-21 



2-01 



1-72 



2-50 



1-25 



1-66 



F none 



•11 



1-03 



1-23 



•24 



•77 

 100-19 



•37 



99-95 



99*80 



100-21 



100-38 



100-35 



100-22 



equiv- 















alent to 















F -00 



•05 



•43 



•53 



•10 



•32 



•15 



99'9i 



99 



99-7 



99 



100-25 99" 



100-0' 



* The water was determined by absorption by calcium chloride. See 

 Hillebrand, Analysis of Silicate and Carbonate Eocks, Bull. U. S. Geol. 

 Surv., 305, p. 62. 



f Analyses 6 and 7 were made by Penfield and Stanley. 



