688 PROFESSOR T. ANDERSON ON THE 
I II. III, 

Carbon, ‘ ‘ ‘ 34:16 33°94 33°95 33°87 C, 168 
Hydrogen, . : : 1:39 1-66 1-66 Pol oe 8 
Bromine, : : : Aa ti an 64:52 Br, 320 
100:00 496 
This gives for the constitution of the compound C,, H, Br, a somewhat un- 
usual formula, differing from that of most similar compounds. In general, when 
a bromide or chloride of an organic compound is treated with potash, one half of 
the haloid is removed in combination with hydrogen, the remainder passing into 
the radical. In this case, however, only two equivalents of hydrogen are removed, 
and the formula of the compound ought in all probability to be written C., H; 
Br, + Br,. 
Action of Chlorine on Anthracene. 
The examination of the compounds produced by the action of chlorine on 
anthracene is attended with some difficulty, the changes occurring being of a 
somewhat complicated kind; more than one substance being generally obtained, 
and the nature and proportion of the products depending very greatly on the 
circumstances of the experiment. Chlorine is readily absorbed by anthracene in 
the cold; and if the current is rapid it becomes warm, gives off hydrochloric acid 
in abundance, and is eventually converted into a hard cake. If the chlorine be 
passed through it in a slow current, the evolution of hydrochloric acid is greatly 
diminished, although it cannot be altogether avoided ; and when this is done, 
and the chlorine is not continued too long, the principal product is bichloride of 
anthracene. 
Bichloride of Anthracene.—The mass obtained by the action of chlorine dis- 
solves readily in benzole, and on cooling, groups of radicated needles, often of 
considerable length, are deposited. The bichloride is readily soluble in alcohol, 
but only very sparingly in ether. When crystallised from alcohol, it is very 
liable to lose hydrochloric acid, and this change always takes place to some 
extent, which causes a slight excess of carbon and deficiency of chlorine in 
analyses :— 
12-564 grains of carbonic acid, and 
5:074 grains of bichloride of anthracene gave 
if 
1-795 grains of water. 
f 4614 grains of bichloride of anthracene gave 
II. 4 11-524 grains of carbonic acid, and 
1-717 grains of water. 
Tin. J 4-474 grains of bichloride of anthracene gave 
*{ 5:14 grains of chloride of silver. 

