Chemistry and Physics. 473 
those which are evolved from fissures in the mines. The experi- 
ments were made upon the bituminous, or “house coals; the 
Ww 
“singe in a hard glass tube and connected with a Sprengel pump. 
ery little gas—only 2 or 3 ec. per 100 grams of coal—was liberat- 
ed on exhaustion. The tube was then immersed in boiling water and 
kept there so long as gas was evolved. Additional quantities of 
gas were obtained at 200° and even at 300°, Upon analysis, the 
as well as from the coal itself by boring, consisted almost entirely 
of marsh gas, rising in some cases to 97°65 per cent.—Jour. Chen, 
Soc., II, xiii, Sept., 1875. G. F. B. 
- On rysophanic Acid.—LinBERMANN and Fiscuer have 
continued the researches made upon emodin by the first-named 
a 0 
tions of this hydrocarbon. Acetyl-chrysophanie acid was also pre- 
d. 
the amides of chrysophanic acid.—Ber. Berl. Chem. Ges., viii, 
1102, Sept., 1675. G. F. B. 
7. On the Quantitative Determination of Vanillin in Vanilla, 
—The introduction into commerce of the synthetically prepared 
vanillin renders some method desirable for its exact estimation. 
IEMANN and HaaRmanwn have proposed a method founded on its 
aldehydic nature and its consequent union with acid sulphites. 
Thirty to 50 grams of the finely divided vanilla is repeatedly ex- 
“ a ; 
means of a Separating funnel. e lower, whicl 
vanillin solution, is placed in a flask furnished with funnel and de- 
Am. Jour, Sor,—Turrp SERIES, * bese X, No. 60.—Dec., 1875. 
3 
