470 MR. G. B. BUCKTON AND DR. A. W. HOFMANN’S RESEARCHES ON THE 
Sulphohenzoate of Barium. 
As the filtrate was very dark-coloured, the barium-salt was again decomposed by 
sulphuric acid, and then boiled with excess of oxide of lead, filtered and treated by 
hydrosulphuric acid. The sulphide of lead was found to carry down with it almost 
the whole of the colouring matter. The acid liquid was then saturated with car- 
bonate of barium, a portion evaporated nearly to dryness and treated with hydro- 
chloric acid, when a salt crystallized out from the mother-liquor, which, after wash- 
ing with water, was again crystallized until free from hydrochloric acid. 
Dried at 200 °, it gave a percentage of barium which coincided with that required 
by the acid sulphohenzoate of barium analysed by Mitscherlich and Fehling. 
0'4092 grm. gave 0T768 grm. of sulphate of barium. 
Formula. • Theory. Experiment. 
Ci,(H 5 Ba)S 2 0,o 25-41 25-39 
V . ^ ; 
V 
Acid sulphohenzoate of barium. 
It was therefore obvious that the disulphosalt, if present, was the most soluble, 
and to be found in the filtrate. 
The remaining portion of the neutral solution of the barium-salt was therefore dis- 
solved in water, and about one-half of the solid matter precipitated by alcohol, filtered 
off and recrystallized. 
0 3634 grm., at 190°, gave 0-2510 grm. of sulphate of barium, 
the percentage of barium in which corresponds to the neutral sulphohenzoate of 
barium. 
Formula. Theory. Experiment. 
C ,4 (H 4 Ba^) S 2 Oio 40-65 40-58 
' ' . 
Neutral sulphohenzoate of barium. 
Disulphohenzolate of Barium. 
It remained, therefore, to examine the salt last thrown down by alcohol, which, 
after being purified again by precipitation, gave analytical numbers characterizing 
the new salt, although still in a state of admixture with sulphohenzoate of barium. 
0-4910 grm., at 170°, gave O’SlfO grm. of sulphate of barium, 
which percentage approximates to that of the salt suggested by theory. 
Formula. Theory. Experiment. 
C,,(H,Ba,)S4 0,, 36-72 3770 
This analysis could leave no doubt regarding the nature of the substance analysed, 
yet it was desirable, if possible, to prepare the new compound in a state of purity ; 
and the question presented itself, whether it could not be more directly formed from 
sulphobenzolic acid, C 12 Hg SaOg, which is so easily obtained by the action of sul- 
phuric acid upon benzol. Success in its preparation by this means was of consider- 
