G. J. Brush on Tephroite. 69 
_ mine them to be members of the feldspar group. The mineral 
that I found at Stirling exhibited a beautiful and vivid green 
phosphorescence when struck with a hammer ina darkened room. 
The broad cleavage surface is striated with fine parallel lines. 
Analyses made by Messrs. Peter Collier and Arnold Hague under 
my direction in this Laboratory gave the following composition. 
o. 1, brown variety, analyzed by P. Collier. No. 2, red va- 
riety, analyzed by A. Hague. 
Oxygen. 2. mere 
Silica, 80°55 16°29 31-73 2 
Manganous oxyd, 52°32 11-79 4762 10°73 } 
Ferrous oxyd, 1°52 vt | 0°23 05 | 
Magnesi 73 309 $1684 14°03 561 17-48 
ime, 1-60 0-45 0°54 O15 
Zinc oxyd, 5-93 117 41'T 0:94 
Ignition, 0-28 0-35 
99:93 G.=2°97 99-27  G.=2'87 
Both minerals were associated with zincite, disseminated in the 
same manner as in the original tephroite, and the oxyd of zine 
given in the analyses is undoubtedly due to this impurity. Des 
Cloizeaux has also published analyses of two specimens of this 
mineral, in both of which zincite was present as a mechanical 
impurity. These analyses, made by Deville* and Damour,’ gave 
the following results: 
Bi n M, €a Zn Ign. : 
2837 = 59-31 2-16 2-16 0°39 7°58 —= 99:97 Deville. 
29°95 = 36-43 196 «61860 «=6©——_—i11 61 1°71=10026 Damour, 
Excluding the oxyd of zinc in my analysis, and in those by 
Collier, Hague, Deville and Damour, we have— 
Bi Mn Fe Mg Ca Ign. 
1. 307 6577 109 189 104 0-87== 9993 Brush. 
Oxygen, 1614 1482 024 056 080 
6 2. 8070 866417 = 284 234 042 ——== 99°97 Deville. 
xygen, 1637 1446 0682 094 O12 ? 
Phe 3248 5562 1°61 322 170  030== 99°93 Collier. 
yeen, ‘1732 1253 036 (829 . 04 
a $553 5002 «024 «1474S = O'BT== 99-27 Hague. 
xygen, 1778 1127 - 005 590. 016 
. 3388 4120 2922 2103 —— 193=10026 Damour. 
Oxygen, 1780 9:28 049 8-41 
The ratio of the oxygen of the silica to that of the bases in 
No. 1, is 1614: 15-92. No.2, 16:37:1604, No. 3, 17°32: 16°66. 
* Des Cloizeaux, Manuel de Mineralogie, i, 38. ° Ann. des Mines, loc. cit. 
