- Monosulphid of Potassium and Bromid of Ethylene. 395 
~ When dry chlorine gas is passéd over the sulphid of ethylene, 
this latter is attacked with energy, and chlorhydric acid is given 
off, even though pains may have been taken to prevent the tem- 
perature from rising; chlorhydric acid is also disengaged when 
chlorine is passed into a solution of the crystals in the bisulphid 
of carbon. 
Bromine unites directly with the sulphid of ethylene, form- 
ing a definite compound, and if care has been taken to prevent 
the temperature from rising, no bromhydric acid is given off. 
A determination of density of vapor was made, by Dumas’ 
method, on a portion of the crystals purified by repeated crys- 
tallization from bisulphid of carbon. The substance which re- 
mained in the balloon was entirely unaltered at the temperature 
(266°) of the experiment. 
Temperature of balance, pe: 242.0 
a “ oil-bath, ag 
Increased weight of balloon, 0°5535 
Capacity of ; 348 cubic centimetres, 
Air remaining in s c. ¢. 
Barometer during the time of the experiment =766'8 mm. 
4°213 
_ Another determination, made at the boiling point of mercury 
by Deville’s method, failed, because the substance was decom- 
posed at this temperature. 
The determination given above necessitates the doubling of 
the empirical formula, C,H,S, of the sulphid of ethylene, in 
der to make it the rational formula in accordance with the law 
of Ampére: that one molecule of all bodies in the gaseous form 
occupies two volumes of space, if one atom of hydrogen is con- 
sidered as occupying one volume. The sulphid in question 
would thus be the product of the condensation of two molecules 
_ of monosulphid of ethylene into one. 
. Condensed products of this nature, belonging to the ethylene 
group, have been made known by the researches of Wurtz and 
2 mY lene isin 3h and the still more condensed compounds of 
ity of ethylene, combine with two equivalents of bromine, 
play the same part in the glycoles derived from them as the 
