WHICH NITROGEN IS SUBSTITUTED FOR HYDROGEN. 
687 
It is easily soluble in water, difficultly so in alcohol, and almost insoluble in ether. It 
does not contain any water of crystallization. After drying over sulphuric acid it does 
not lose weight, even when heated to upwards of 160° C. 
I. 0-5535 grm. of the salt, dried at 160°, gave 0-3112 grm. of carbonic acid and 
0-0443 grm. of water. 
II. 0-9153 grm. gave 0-5433 grm. of carbonic acid and 0-0726 grm. of water. 
III. 0-502 grm. gave 0-3082 grm. of chloride of silver. 
IY. 0-4975 grm. gave 0-302 grm. of chloride of silver. 
These numbers lead to the formula G 6 H 4 -S 2 Ag 2 0 7 . 
Theory. 
Av 
Experiment. 
^6 
72 
15-39 
' I. 
15-33 
ii. 
15-29 
III. 
IY. 
H 4 
4 
0-85 
0-89 
0-88 

— 
s 2 
64 
13-68 
— 
— 
— 
— 
A g 2 
216 
46-15 
— 
— 
46-20 
45-69 
0 7 
112 
23-93 
— 
■ 
— 
— 
468 
100-00 
To judge from the composition of the silver-salt of disulphophenylenic acid, it appears 
to be bibasic (G 6 H 4 -S 2 H 2 0 7 ), whilst the formula deduced from its barium and lead salts 
establishes its tetrabasic character (G 6 H 4 -S 2 H 4 0 8 ). The new acid exhibits therefore 
the rare property of varying basicity, such as is possessed by phosphoric acid in the in- 
organic, and by terebinic acid in organic chemistry, as shown by Ekman*. 
Action of Sulphuretted Hydrogen upon the Gold-salt of Hydroehlorate of Diazobenzol. 
By passing a current of sulphuretted hydrogen gas through cold water in which the 
gold-salt has been suspended, all the gold is converted into the trisulphide, whilst the 
diazobenzol is transformed into a volatile product. When the reaction is complete, the 
liquid is submitted to distillation, when a very nauseous, heavy, yellowish oil is found to 
pass over with the aqueous vapour. I have not pursued its examination further than 
to convince myself that it is not the phenylmercaptan (G 6 II 6 -S) described by Vogt, 
which at first sight it appeared to be. Its mercaptanic odour and its derivation from 
the diazobenzol in the gold-compound (according to the equation 
G 6 H 4 N 2 +£H 2 =G 6 H 6 S+N 2 ) 
rendered this view very probable. Neither basic acetate of lead, however, nor nitrate of 
silver, even in the presence of ammonia, gave precipitates with the oil, which proved 
convincingly that it differed entirely from phenylmercaptan. 
On examining the residue in the retort after the oil had been distilled off, it was 
found to consist of tersulphide of gold and an aqueous liquid ; the latter is found to con- 
tain chloride of ammonium, together with a little free hydrochloric acid, and a small 
* Limpricht, Lehrbuch der Chemie, p. 1016. 
