Mr. A. Williamson's Theory of JEtherification. 353 



retted hydrogen of iodide ofaethyle, as by the inverse process 

 described above. This I have verified in the case of the three- 

 carbon aether, which may be obtained indifferently by repla- 

 cing one-fourth of the hydrogen of methylic alcohol by C 2 H 5 , 

 or by replacing one-sixth of the hydrogen of common alcohol 



C 2 H 5 

 by CH 3 . Its rational formula is therefore n U13 O. 



C H 3 . . 



By acting upon the compound T ^ O by iodide of amyle, 



I obtained a third aethereal compound, of which the formula 



C H 3 



is ps pjii O. This is evidently the only one of the three new 



aethers, which, containing an even number of carbon atoms, 



might be conceived to have been formed from one alcohol ; 



but when treated with monobasic acids, as hydrochloric, it 



cannot be expected to act in the same manner as its homoge- 



C 3 H 7 

 neous isomeric, the aether p 3 ny Oof the three-carbon alcohol 



C 3 H 7 ... 



tt O ; but of this I will give an exact account in the paper 



above alluded to. 



My task is now to explain the process of aetherification by the 

 action of sulphuric acid (SO 4 H 2 J upon alcohol ; and in order to 

 accomplish that, I must show the connexion between those sub- 

 stances and the reagents used in the above-described experi- 

 ments. With this view, I have merely to add to the above 

 facts the acknowledged analogy of the simple and compound 

 radicals in their compounds. I must first show how a sub- 

 stance analogous to my iodide of aethyle is formed, and then 

 how by double decomposition with alcohol it produces aether. 

 This is very easy ; for sulphovinic acid is strictly analogous 

 to iodide of sethyle plus iodide of hydrogen, which we should 

 obtain by replacing SO 4 in its formula by an equivalent of 

 iodine; and in order to represent the formation of this sul- 

 phovinic acid, which is well known to precede that of aether, 

 the simplest mode is at the same time the one most free from 

 hypothesis ; it consists in stating the fact, that sulphuric acid 

 and alcohol are transformed into sulphovinic acid and water, 

 by half the hydrogen of the former changing places with the 

 carburetted hydrogen of the latter : thus — 



H S ° 4 C 2 H* S ° 4 



C2H5 o H o 



H u II u 



Now from this point it is clear that the process is the same as 

 in the decompositions above described ; for by this sulphovinic 

 Phil. Mag. S. 3. Vol. 37. No. 251. Nov. 1850, 2 A 



