336 Dr. Thomas Thomsons 



If we admit the fluoric acid to have been in combination 

 with lime, that base will be reduced to 2-55 atoms. The 

 atoms of bases amount to 27-85 ; while those of silica are 

 9-68. Now the third part of 27-85 is 9-28. Hence, it is 

 evident, that the mineral consists of tri-silicates or of three 

 atoms of base combined with one atom of silica. The for- 

 mula for its composition will be 



Zr 



11 Al'S + 2MgsS + 1| Cal 3 S + { f S>'S + 2Aq. 



(^ mn ) 



It is a quadruple aluminous salt, and its place may be 

 between mountain leather and pearl-stone in vol. i. p. 390 of 

 my Mineralogy. 



If, by bronzite be understood what is usually called schil- 

 ler spar, then holmite is a quite distinct mineral. 



III. — ANTHOPHYLLITE AND SCHILLER SPAR. 



In a parcel of minerals which Dr. Holmes, of Montreal, 

 was so obliging as send me during the course of the present 

 winter, there was a pretty large specimen, the locality of 

 which was stated to be Perth, Upper Canada. It consisted 

 of a congeries of imperfect crystals having a good deal of 

 the aspect of anthophyllite. Its specific gravity was 2-707, 

 and its constituents were found to be, 



99-3 

 Hence, the constitution is, 



4 Mg S* + -<J Al + a Cal + i/) S* + Aq. 

 If the reader will turn to page 207, vol. i. of my Miner- 

 alogy, and compare the analyses of anthophyllite, he will 

 be satisfied that the American mineral is an anthophyllite 

 as its external characters indicate. But in the specimens 

 of anthophyllite analysed by Vopelius, L. Gmelin and my- 

 self, it will be seen, that there were not less than 13 parts 



