68 G. J. Brush on Tephroite. 
original tephroite are similar to those of chrysolite, and that 
this isomorphism is further sustained by the chemical composi 
tion of the minerals, both being represented by the general for- 
mula R3Si. 
Before the blowpipe, tephroite fuses easily to a black mass; 
fusibility =8°5 on v. Kobell’s scale. With the fluxes, gives Te 
Oxygen, 
Biion 802 me wig eo 7 8019 1610 1610 
usoxyd,- - - 65°59 14°78 
Ferrous oxyd, - - - 1-09 0-24 | 
i RCE Hatt eS ‘1:38 0°55 } 15°92 
ime, ~ z * - - 104 0:30 
Zinc oxyd, - - - - 0:27 0-05 | 
jeniiion, => = 4 6 . 0°37 
99°93 
the cleavage surfaces almost flesh-red. Both specimens were 
less fusible than the original tephroite, the brown variety “a 
bi hagas 
to 5 of v. Kobell’s scale. In all other physical characters these 3 
gravity, most mineralogists would, on a mere inspection, deter 
