232 W. G. Mixter on Willemite and Tephroite. 
free it 
a white enamel, turns black and gives a black glass on 
Two analyses of the mineral selected with great care to 
from the zincite yielded: 
2, e. 2. Mean. 
Silica, * 29°42 29°46 29°44 
Zine oxyd,.----- 7°36 7°36 7:36 
Manganousoxyd, 5755 57°07 57°31 
Ferrous oxyd,... 0°89 0°84 0°87 
Lime, 2°51 2°52 2 
, Magnesia, -..-.-. 2°49 2°51 2°50 
Ignition, --...-- 0°27 0°27 0°27 
100°49 = 100°03 100°26 
manganous oxyd than obtained in any other analysis 
merican mineral, The ash-colored mineral, as appeals 
the analysis, is proven to be tephroite. It bears a close 
ce to a specimen of the original tephroite ! 
Prof. Breithaupt by Prof. Brush, but it was first 
it differed from this chemically in having a portio 
co a 
through it minute specks of pale green, almost white, 
ite, and it was not end practicable to select the tep2 
he analyses are of interest as identifying the ash- 
of tephroite originally described by Broa 
0h t been re-di 
in considerable abundance at the north end of J 
_ may be readily distinguished from willemite b; 
t, its pyrognostic characters, and its ordinary ' 
New Haven, June 25th, 1868, 
