ETHIONIC AND ISETHIONIC ACIDS. 779 



the action of anhydrous sulphuric acid on absolute alcohoL A 

 crystalline compound of olefiant gas and anhydrous sulphuric 

 was obtained by M. Regnault, which may be separated by C 4 H 4 

 + 4SO 3 , or by C 4 H 4 O,S 2 O 5 + 2SO 3 , that is, as containing hypo- 

 sulphuric acid united with another base, different from oxide of 

 ethyl, with sulphuric acid. A crystalline compound was also 

 obtained by Magnus, by exposing absolute alcohol to the vapour 

 of anhydrous sulphuric acid, and named by him carbyle, which 

 appears to be the same. Saturated with carbonate of barytes, 

 carbyle gave free sulphuric acid and the soluble ethionate of 

 barytes, which last contains the same elements as sulphovinate 

 of barytes, indicating the assumption of the elements of an atom 

 of water by the carbyle. Ethionic acid may be procured by 

 adding dilute sulphuric acid cautiously to a solution of ethionate 

 of barytes. It is a compound of small stability, and is decom- 

 posed by boiling like sulphovinic acid, giving alcohol and isethi- 

 onic acid, the last of which does not undergo farther decompo- 

 sition. The salts of the latter are likewise isomeric, when dried, 

 with the sulphovinates. Isethionic acid may be concentrated, 

 and stands 302 (150 cent.) without decomposition. All its 

 salts are neutral to test-paper, and are also remarkably stable, 

 supporting a temperature of 482 (250 cent.) without decom- 

 position. When fused with an alkaline hydrate, they leave as a 

 residue a mixture of the sulphite and sulphate of the alkali, 

 from which it is inferred that they contain hyposulphuric acid, 

 and not sulphuric acid. 



Isethionate of barytes is prepared by passing pure olefiant gas 

 througli anhydrous sulphuric acid, in the liquid state ; or by 

 saturating ether in a flask surrounded with ice, by the same 

 acid. The acid solution is afterwards boiled, so long as alcohol 

 is disengaged, and then saturated with carbonate of barytes. 

 This salt is represented by BaO,C 4 H 5 O 2 + S 2 O 5 . Isethionate 

 of copper crystallizes in regular octohedrons, of an emerald 

 green colour, containing 2 atoms of water of crystallization, 

 which they lose at 482 (250 cent.), and become white and 

 opaque. From none of these salts can alcohol or ether be de- 

 rived ; they do not, therefore, contain ethyl. 



Two other acids of this class have been obtained, methionic 

 acid, by saturating ether with anhydrous sulphuric acid, without 

 cooling the mixture, of which the salt of barytes, BaO,C 2 H 3 S 2 O 7 , 



