7 
Ordinary Meeting, October 29th, 1878. 
J. P. Joule, D.C.L., LL.D., F.R.S., &c., President, in the Chair. 
“Note on certain Thionates,” by E. J. Bevan, Student in 
the Owens College. Communicated by Professor H. E. 
Roscoe, F.R.S., &c. 
Thallium Triothionate. When thallium carbonate is 
treated with an equivalent quantity of trithionic acid, pre- 
pared by precipitating potassium tritbionate with tartaric 
acid, and the aqueous solution so obtained evaporated over 
strong sulphuric acid, thallium trithionate separates out in 
long colourless needle-shaped crystals isomorphous with 
those of the corresponding potassium salt. Thallium tri- 
thionate decomposes slowly at the ordinary temperature, 
quickly on heating, and is with difficulty prepared free from 
sulphate. Analysis showed it to contain 08% of thallium, 
whereas the formula K 2 S 3 0 6 requires 67'95%. 
Hypovanadic Dithionate . — If an aqueous solution of 
barium dithionate be precipitated with the requisite quantity 
of hypovanadic sulphate, and the blue filtrate from the 
barium sulphate concentrated in a vacuum over strong 
sulphuric acid, crystals of hypovanadic dithionate separate 
out. If concentration be continued after the first appearance 
of these crystals, decomposition takes place, sulphur dioxide 
is set free, and hypovanadic sulphate remains. This easy 
decomposition prevents hypovanadic dithionate being pre- 
pared in the pure state. 
Aniline Dithionate — This salt is obtained in beautiful 
long needles, by the double decomposition of barium 
dithionate with aniline sulphate. Aniline dithionate is 
comparatively stable, its aqueous solution may be boiled 
without decomposition, when the dry salt is cautiously 
heated in a vacuous tube it sublimes, a portion, however, 
undergoing decomposition. It is freely soluble in water 
and alcohol; 100 c.c. of water at 16° dissolve 7’89 grms. of 
the salt. Its alcoholic solution, treated with sodium 
amalgam, yields aniline sulphite. Analysis showed this 
Proceedings— Lit, & Phil. Soc,— Yol. XYIIL— No. 2.— Session 1878-9. 
