DR. KANE ON THE CHEMICAL HISTORY OP ARCHIL AND LITMUS. 
317 
It is probable that this azolitmate of tin may be the more definite of the two, as 
possibly an excess of ammonia may have produced the formation of the more basic 
salt formerly described. When this salt, diffused through water, is mixed with a 
small quantity of muriatic acid and boiled for some time, it becomes whitish or 
slightly fawn-coloured, and the tin is found to have been changed into peroxide. A 
quantity of the tin makes its appearance as peroxide uncombined, but the greater part 
remains united with the leucazolitmine. I found the difficulties of procuring this 
compound in its white form proper for analysis, to be insuperable. Even in the best 
exhaustions I could produce, it gradually became red ; and when exposed even for a 
short time to the air, it forms a bright scarlet lake, remarkably distinct from that 
produced by the protoxide of the same metal. I consequently was not able to analyse 
the leucazolitmate of tin, or to obtain at all the same evidence concerning it that I 
did with regard to leucorceine. 
I allowed a quantity of leucazolitmate of peroxide of tin diffused through water, to 
lie exposed to the air in a flat dish until it was completely converted into the scarlet 
substance. This was then dried at 212° and analysed, there being some peroxide of 
tin mechanically diffused through it, but not much. 
0‘652 gramme gave water 0’215, and 0"658 of carbonic acid. 
IT 07, by ignition and treatment with nitric acid, gave 0-443 of peroxide of tin. 
The resulting formula is C 18 H ]2 N 0 16 Sn 2 , giving 
1 8 Carbon . 
Theory. 
Experiment. 
109-8 
28-77 
27*93 
12 Hydrogen 
12-0 
3-14 
3-66 
1 Nitrogen . 
14-1 
3-69 I 
36-93 
16 Oxygen . 
128-0 
33-54 J 
2 Tin . . 
117*8 
30-86 
31-48 
3817 
100-00 
100-00 
This salt, exposed to a temperature of 280° in an oil bath, loses 4 - 5 of water or two 
equivalents, and hence when dry is C 18 H 10 N O 10 + 2 Su 0 2 . 
The blanching of azolitmine by hydrogen can easily be effected by precisely the 
same means as were described under leucorceine, but the restoration of the colour 
occurs so rapidly and from such slight access of air, that it must be considered as 
still more difficult to isolate the white condition than the orceine. I consequently 
was not able to analyse the leucazolitmate of zinc, and the proofs of its being 
similar in constitution to leucorceine must rest on analogy alone. 
An additional reason for looking on these bodies as being produced by the addition 
of hydrogen and not by the abstraction of oxygen, is the fact, that where there are so 
many formed by the absorption of oxygen from the same source, the subsequent re- 
moval of oxygen should regenerate the bodies lower in the scale, in place of produ- 
