32 



Pin field and Stanley- 



The material used for analysis floated on the heavy solution at 

 2-984 and sank at 2-975, the average being 2*980. " The results 

 of the analysis are as follows : — 



Per cents of 

 protoxide bases 



•963 





I 



II 



Average 



Ratio 



SiO„ 



57-61 



57*78 



57-69 



•961 



Ti0 2 



•14 



•14 



•14 



•002 



A1.0 3 



1-85 



175 



1*80 



■018' 



Fe'A 



•00 



•00 



•00 



•000 



FeO 



"55 



•55 



•55 



•007 



Mi.O 



trace 



trace 



trace 



•000 



MgO 



24-12 



24 12 



24-12 



•606 



C»0 



13-07 



13*30 



13-19 



•236 



K 2 



•22 



. 



•22 



•002 



Na 2 



•48 







•48 



•008 



H 2 Q 



1-76 



1*61 



1-56 



•087 



f; 



•3 7 







•37 



•on 



Loss at 110° 





•10 





•018 



} *954 



0-7 

 ()•() 

 63 5 

 24*7 

 0-2 

 0*8 

 9-0 

 1-1 



100-0 



64-2 



0=F. 



100*22 

 •15 



100-07 



ACTINOLITE. 



Of the green variety of amphibole, characterized by a low- 

 percentage of sesquioxides and commonly known as actinolite, 

 four varieties have been analyzed. As regards localities, 

 association and mode of occurrence they are as widely sepa- 

 rated as possible. 



III. Actinolite from Greiner in Tyrol. Specimen No. 

 34-9, Brush Collection. — This is one of the well known locali- 

 ties, where crystals of a fine, dark-green color, showing the 

 combination of the prism m (110) and pinacoid o (010), occur 

 imbedded in talc. T<5 obtain material for analysis the crystals 

 were first carefully selected by hand, and as they were found 

 to be coated with a fine talcose powder, they were treated for a 

 while with a mixture of warm dilute hydrofluoric and hydro- 

 chloric acids, which left them clean and brilliant. When broken 

 up and sifted to an uniform grain the fragments were found 

 to be wonderfully pure when studied with the microscope. 

 A very small proportion of the particles were found to con- 

 tain minute black grains, presumably of magnetite, but these 

 being heavier were removed by treatment with the heavy 

 solution. The material for analysis floated at 3*058 and sank 

 at 3*036, the average specific gravity being 3*047. 



The results of the analysis are as follows : — 



