Chemistry and Physics. 379 
gold-yellow plates, the ot 
bodies proved to be mono- and tri-acetyl-emodin and led to the 
concludes that emodin is a tri-oxymethylanthraquinone of the 
following formula: 
- matter which shows a marked analogy with those of log- 
Water, was precipitated in red-brown light flocks. It was puri- 
fied by reduction, and was obtained as a dark green powder with a 
Strong metallic luster, nearly insoluble in boiling water, but solu- 
— ble in alcohol, ether, and acetic acid with a deep brown, and in 
alkalies with an intense purple color. Owing to the difficulty of 
ts combustion, its nitrogen was at first overlooked, ri- 
z The empi 
cal formula C,,H,,NO, is assigned to it, the rational formula 
C,H, OH 
founded on this, deriving it from ammonia N C,H, i a 
C,H } OH 
ror’ OF 
© great similarity of phlorein to hematein and brazilein led the 
author to repare these bodies and to analyze the e found that 
Wise similarly constituted. He writes phlorein as 3(C,H,O,)N 
~(H,0),, hematein as 3(C,,H,,0,)N and brazilein as 
ue of 2H,,0,)N . Phlorein, however, yields a hydroderivative.— 
Liebig’s Annalen, elxxviii, 92, Aug., 1875 . 
3 > 
Ul. Arithmetical relations betwee 
