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XIV.—On the Action of Sulphide of Potassium upon Chloroform. By W.W. J. 
Nicot, M.A. Communicated by Professor Crum Brown. 
(Received 23d January 1880. Read 2d February 1880.) 
In the “Journal fiir praktische Chemie,” [2] 6, 99, Pranxucn states that 
“when one adds chloroform to an alcoholic solution of sulphide of potassium 
a reaction takes place often with explosive violence, and by repeated extrac- 
tion of the mass with absolute alcohol one obtains a compound which 
crystallises from alcohol in long prisms, and may be considered as a double 
salt of sulphide of potassium and sulphoform.” 
On searching for some record of the discovery of sulphoform (H,C,S,), I 
found in the “ Journal de Pharmacie,” xxiii. 12, that BoucHARDAT claimed to 
have prepared sulphoform by the action of iodoform on red sulphide of mercury, 
and, after describing its properties, stated that he had not confirmed his results 
by an elementary analysis, and that it appeared to him “ that the body so formed 
retained a certain proportion of iodine the same as chloriodoform, so that the 
name sulphiodoform would be more suitable than that of sulphoform.” 
As a great deal of uncertainty seemed to surround this point, I thought that 
it might be interesting to repeat the experiments of Prankucu, and if possible 
to obtain some accurate knowledge of the products of the action of sulphide of 
potassium on chloroform. 
I therefore prepared a quantity of alcoholic sulphide of potassium by dissolv- 
ing caustic potash in alcohol, dividing the solution into two parts, saturating the 
one with sulphuretted hydrogen, and then adding the remainder. On mixing 
a few drops of chloroform in a test-tube with a little of the sulphide of potas- 
sium thus prepared, and gently warming, a reaction took place with such violence 
that the contents of the test-tube were projected to some distance.. On repeat- 
ing the experiment, taking care to add the chloroform in very small portions at 
a time, the solution boiled violently from the energy of the reaction, and a 
quantity of chloride of potassium separated out, reminding me of the action of 
chloroform on alcoholic caustic potash, where chloride and formiate of potas- 
sium are produced ; and I began to hope that one of the products of this reac- 
tion might be thioformic acid (a body analogous to KEKUL#’s thiacetic acid, 
where one of the atoms of oxygen in the group COOH. is replaced by sulphur), 
regarding which very little, if anything, is known ; the only notices of thioformic 
acid that I could find being as follows :— 
Limpricut, in the “ Annalender Chemie und Pharmacie,” xcvii. 361, states 
that during the preparation of formic acid by passing dry sulphuretted 
VOL. XXIX. PART II. 6U 
