366 PROCEEDINGS OF THE ACADEMY OF 



ducing the new compound ; since both the oxides dissolve in water. 

 Wiien under these circumstances none of tlie constituents of the 

 older mineral separates, it is self-evident tliat tliey will all present 

 themselves in less quantit3^ in the newly formed combination than 

 in that from which it was derived. If a silicate of lime had simph^ 

 been mixed with tiie Trautwinite, hydrofhloric acid would have 

 affected it. But the acids have no action upon it; hence it is 

 very probable that the silica and lime combined with the chromite 

 form the mineral which we call Trautwinite. 



The death of Theodoi:e E. Moss was announced. 



October 21. 

 The President, Dr. Ruschenberger, in the chair. 

 Twenty-nine members present. 



Stihiaferrile^ a ew; 3Iineral from Santa Clara County^ Cali- 

 fornia. By E. Goldsmith. The mineral occurs on Stibnite, and 

 enters the rock on both sides. The Stibnite between the two 

 la^-ers of the new mineral is H inch thick; and this appears to 

 be the thickness of the vein at the spot whence the specimen was 

 taken. The layers of the Stibiaferrife vary in thickness from a 

 thin coating to about a quarter of an inch. 



The most of it is amorphous. On examining a number of spe- 

 cimens, I observed some snuiU cavities containing, I believe, the 

 same substance in crystals. The crystals, when ol)served under a 

 power of a 5 lens, have the habitus of ortho-rhombic prisms. 

 They are generally attached by one end, but a few extend to the 

 other side of the cavity. The termination is the basal plane ; I 

 could not find a crystal having a finite pyramid ; the infinite 

 pyramids were those of the first and second order. The measure- 

 ment of one of the crystals, which had a favorable position for 

 observation, was performed with a goniometer (Leeson's) belong- 

 ing to Mr. Clarence S. Bement. Although I made several efforts 

 to get the exact angles of the crj'stals, yet I wish it to be under- 

 stood that the values obtained are only approximate. 



Tiie following are tiie indices or symbols of the observed forms 

 according to the three authors : 



Miller . 



Naumann . 

 Dana . 



100.001 



100.010 



001.010 



110.110" 



110.110' 



110,010 



110,001 



