196 Penfield and Howe — Chemical Composition 









Brewster. 



Mte. Somma. 



Theory where 

 F:OH'= 1: 1. 



SiO., 

 MgO 

 F 

 H 2 0. 







34-56 



59-69 



5-44 



.. 2-62 



34-52 



59-56 



5-25 



2-88 



35-29 



58-82 



5-59 



2-65 





toF = 







0. eq. 



102-31 

 2-31 



102-21 

 2-21 



102-35 

 2-35 



Si0 2 _ 

 MgO 

 F 

 HO. 







"Warwick. 



34-91 



59-23 



7-54 



.. 1-51 



Kafveltorp. 



34-42 



59-90 



6-81 



1-73 



Theory where 



P:0H = 2: 1. 



35-22 



58-71 



7-44 



1-76 





to 



F = 







0. eq. 



103-19 

 3-19 



102-86 

 2-86 



103-13 

 3-13 



These analyses are all slightly high in magnesia and corre- 

 spondingly low in silica and (F+OH), but on the whole they 

 agree very well with the theory. 



Previous analyses of chondrodite. — In discussing the analy- 

 ses of other investigators it must be borne in mind that water 

 has usually been disregarded or determined incorrectly. We 

 have tabulated below the available analyses that have been 

 made on material of known crystallographic character. 



From Mte. Somma. 



I. Rammelsberg.* Brownish yellow crystals. Mean of two 

 analyses. 

 II. G. vom Rath. Light yellow crystals. Mean of two 

 analyses. 



III. Wingard. Light wine yellow crystals. Mean of two 



analyses. 



From Kafveltorp, Sweden. 



IV. Wingard. Wine yellow crystals. Mean of three analyses. 

 V. G. vom Rath. Mean of two analyses. 



VI. Hj. Sjogren. f Brown crystals. 

 VII. Hj. Sjogren. Yellow crystals. 



From Brewster, JV. T. 

 Garnet red crystals. Measured and identified 



VIII. Hawes.J 



by E. S. Dana 



Mean of two analyses. 



*Pogg. Ann., lxxxvi, p. 413, 1852. 

 f Zeitschr. Kryst, vii, p. 356, 1883. 

 % Trans. Conn. Acad., hi, p. 86, 1874. 



