ACTION OF SULPHURIC ACID UPON THE AMIDES AND NITRILES. 473 
with two additional equivalents of sulphuric acid in order to furnish the compound 
C 4 H 4 S 4 Oi 6 =C 4 H 4 O 4 4 SO 3 ? The experiments hitherto detailed contain no evidence 
against this assumption. It appeared to us extremely probable that sulphacetic acid, 
when submitted to the action of sulphuric acid, is converted into disulphacetic acid, 
which, losing carbonic acid, produces disulphometholic acid, the deportment of 
disulphacetic under the influence of heat being closely analogous with that of acetic 
acid, 
C4 H4 O4— 2C02=C3 H4 
Acetic acid. 
Marsh-gas. 
C 4 H 4 O 4 4S03-2C0,=C3 H 4 4 SO 3 
V 
Supposed 
disulphacetic acid. 
Disulphometholic 
acid. 
We have endeavoured to decide this question by experiment ; but on account of 
the greater stability of the benzoic molecule, we have preferred to trace the inter- 
mediate acid in the benzoyl-series. 
Sulphobenzoic acid, obtained from the acid barium-salt, was evaporated to dry- 
ness and heated until it attained the point of quiet fusion. When cold, the acid was 
coarsely powdered, and mixed with rather more than its own bulk of crystallized 
sulphuric acid. 
It was then heated in a water-bath to a temperature below that at which gases are 
disengaged. This appeared to be just below 85° C. The substances were kept in 
contact at this temperature for eight hours. Finally, the mixture was subjected to 
the heat of boiling water for two hours longer ; after which it was treated in the 
usual way for obtaining the soluble barium-salt. 
The salt thus obtained in no manner differed, either in appearance, reaction, or 
composition, from sulphobenzoate of barium. 
0*3838 grm. of salt, dried at 165° C., gave 0*2630 grm. of sulphate of barium, 
corresponding to 40*28 per cent, of barium. 
For comparison, we append the barium -percentages required for the salts of the 
two acids, and the amounts found by experiment. 
Formula. Theory. Formula. Theory. Experiment. 
C.4(H4Ba3)S3 0,o 40*65 C ,4 (H 4 Ba^) S 4 0,6 32*85 40*28 
"V 
Sulphobenzoate of barium. Hypothetical acid. 
Though the above experiments have failed to realize our hopes of producing disulpho- 
benzoic acid, they by no means disprove the existence of this body, and the possibility 
of producing it under more favourable circumstances. We insist upon this point, on 
account of the success which has attended our endeavours to trace the existence of 
disulpho-acids in a perfectly different group of bodies. 
We are indebted to M. Gerhardt for the knowledge of a conjugated sulpho-acid, 
containing an organic base in the place of hydrocarbons, alcohols, acids, &c., which 
