444 DR T. THOMSON'S Analysis of some Minerals. 



enumeration of the species at present known may not be unac- 

 ceptable to mineralogists : 



1. Sp. Sideroschisolite, or disilicate of iron, discovered in 

 Brazil, and described by Dr WARNEKINK*. It is composed of 



1 atom silica, 2 



2 atoms protoxide of iron, . . 9 



1 atom water, 1.125 



12.128 



2. Sp. Chamoisite, occurring in beds at Chamoisin, in the 

 Valois, and described and analyzed by Berthierf. Its consti- 

 tuents are, 



1 atom silica, .2 



2 atoms protoxide of iron, . . 9 



2 atoms water, ...... 2.25 



13.25 



3. Sp. Cronstedtite, discovered at Przibram in Bohemia, de- 

 scribed by ZIPPE, and analysed by Professor STEINMANN |. Its 

 constituents are, 



1 atom silica, . . . . . . 2 



1 atom protoxide of iron, . . 4.5 

 1 atom water, 1.125 



7.625 



* POGGENDOEFF'S Annalen, i. 387. 

 acmob 



f Ann. des Min. V. 393. 

 gnrwblii 



J SCHWEIGGEE'S Jahrbuch, ii. 69. 



