DR. KANE ON THE CHEMICAL HISTORY OF ARCHIL AND LITMUS. 315 
examine this precipitate in its white form, it was immediately, on being formed, 
thrown upon a filter and placed under the receiver of an air-pump, from which the 
air was removed, and then it was filled with carbonic acid gas. As soon as the 
liquor had filtered through, the filter was filled with warm distilled and recently 
boiled water, and the replacement of the air, by carbonic acid gas, again proceeded 
with. This was continued until the substance was found to have been washed 
enough. 
A dish of oil of vitriol was then placed under the receiver, and the vacuum main- 
tained until the precipitate had become completely dry. In no case did I succeed in 
obtaining the precipitate white when dry. Most frequently it was spoiled altogether, 
becoming purple. But in a case where I obtained it of a uniform pale pink colour, 
it was analysed. 
0*451 gramme of substance gave, by ignition until all organic matter was burned 
off, then moistening with nitric acid, and again igniting, 0*157 of oxide of zinc. 
0*382 gramme of substance gave 0*439 of carbonic acid, and 0*160 of water. 
The formula resulting is C 18 H 14 O 10 N + 3 Zn O, by which the numbers obtained 
are 
Theory. 
Experiments. 
18 Carbon . . 
109*8 
32*41 
31*80 
14 Hydrogen 
14*0 
4*13 
4*66 
1 Nitrogen . . 
14*1 4 
2777 
28*73 
10 Oxygen . . 
80*0 J 
3 Oxide of zinc 
120*9 
35*69 
34*81 
338*8 
100*00 
100*00 
This formula may be rationally assumed as either C 18 H 10 N 0 6 + 3 Zn O + 4 H O, 
or C 18 H 12 N 0 8 + 3 Zn O -}- 2 H O, the decolorized condition being supposed due to 
either a loss of oxygen or gain of hydrogen. In order to compare it with the ordinary 
betaorceinate of zinc, a specimen of fine purple salt was analysed. It had been 
carefully dried at 212° Fahr. 
0*982 gramme gave, by ignition and treatment with nitric acid, 0*331 of oxide of 
zinc. 
0*651 gramme gave 0*235 of water, and of carbonic acid 0*720. 
The resulting formula is C 18 H 14 N 0 12 + 3 Zn O, from which result the numbers:. 
Theory. 
Experiment. 
18 Carbon . . 
109*8 
30*95 
30*53 
14 Hydrogen . 
14*0 
3*95 
4*02 
1 Nitrogen. . 
14*1 I 
31*03 
31*73 
12 Oxygen . . 
96*0 J 
3 Oxide of zinc 
120*9 
34*07 
33*72 
354*8 
100*00 
] 00*00 
2 s 2 
