614 PROFESSOR FREDERICK GUTHRIE 
When the latter body is submitted to the action of chlorine, there is formed 
(6) C, H, S Cl, Chlorosulphide of bichlorethylen, 
A body identical with that got by the action of chlorine upon the bisulphide of 
ethyl— 
(7) C, Cl, § Sulphide of terchlorethyl. 
Further, chlorine acts upon the bisulphochloride of amylen to form 
(8) C,, H, S Cl, -Chlorosulphide of terchloramylen ; 
Moreover, oxide of lead converts the body (4) into 
* (9) C,, H,, 8, 0  Bisulphoxide of amylen, 
while hydrated ammonia and hydrated potash give rise to the hydrate of (9) 
* (10) C,, H,, 8, O HO Hydrate of bisulphoxide of amylen. 
The manner of the formation of these bodies, and the definite and integral 
nature of the reactions which they show, is alone sufficient to prove that they are 
true single chemical compounds, and not mixtures. Since, however, they are 
none of them volatile without decomposition, their boiling points and vapour 
condensation, useful criteria of homogeneousness, are wanting. The same fact, 
however, may be equally well established by another method; that, namely, of 
“‘ fractional solution.’’ This method, which is of very wide application, has been 
already successfully employed in determining the homogeneous nature of gases. 
The principle may be enunciated as follows :— 
‘< If a body be partly dissolved in a solvent, and if the dissolved part and the 
undissolved part, or the dissolved part and the whole, have the same composi- 
tion, then the body is a simple one.” 
The converse of this law is not true, because solution may effect decomposi- 
tion. Nor is the law itself any more or less true than that no two different 
bodies are soluble under the same circumstances to exactly the same extent in 
the same medium. This seems to be true in all cases but where the solubility is 
infinite, or indefinite miscibility possible. 
This method was applied to the bisulphochlorides of amylen and ethylen, 
because, as we shall immediately see, they give rise to numerous derivatives, and 
because their definite nature should be therefore set at rest. 
A few grammes of the bisulphochloride of ethylen were warmed with strong 
alcohol until about half dissolved. The alcoholic solution was poured off, evapo- 
rated to expel the alcohol, then washed with water, and dried over sulphuric acid 
im vacuo. 
On analysis, 
I, 0.4436 gave 25:27 per cent, carbon and 4°36 hydrogen. 
II, 0-4280 gave 33°88 per cent. sulphur. 
III. 0.2838 gave 36:00 per cent. chlorine. 
