262 A. Schrauf and E. 8S. Dana—Thermo-electrical 
endeavored to supply the want approximately by determining 
the specific gravity wherever this was possible.* 
A. Tetradymite. 
Schubkau Orawitza Georgia England babi ie 
+ ~ - = 
Te 34°6 35°9 48°7 29°7 
} 4°8 4°2 0° ? 2°3 
Bi 60-0 59°38 51°5 61-1 
Fe 
Ag 0% 2-0 
Wehrlet | Frenzelt{| Balch | Wehrle § 
c= 7°30 7868 
Wehrlet Balch & 
B. Danaite. 
Léllingite. 
Franconia. | Hakansbé. | Skutterud. | Modum. FegAss_ 
Reichenstein. 
eee bi ee oo sn as 
a 6°335 6°096 6°159 
As 41°7 46°7 65°8 
17°8 17°4 1°8 
Fe 32°9 26°2 32°3 
Co 674 971 
Hayes.** Scheerer.++ Karsten. ff 
G= 6°207 6°08 
6°059 
Variety Ver- Variety 
montite from | Akontite from| 
Franconia. | Hakansbd.| 
* Each of our specific vity determinations is the mean of several trials. The 
ity 
mean error may be stated as + 0-002, 
Wehrle, Schweigg. J., 1830, vol. lix, 482. + Frenzel, Leonh, Jahrb., 1873, 800- 
Balch, Amer. Jour. Sci., I, vol. xxxv, p. 99. 
‘{ Balch, Dana Min., 1870, p. 31. ** Hayes, Am. Jour. Sci., II, vol. xxiv, p. 386- 
f Scheerer, Pogg. . p. 546. 
Eien Dana Min., 1870, p. 78. [| Dana, Min., 1870, p. 79. 
