38G lIEINRICn ROSE ON ^ETIIERIFICATION. 



logons to that of aether, which, when it has been once separated 

 l)y boiling from a mixture containing sulphovinic acid, appears 

 not to combine directly with acids. 



NOTE. 



Our readers will be able to judge bow far tbc tbcovy of rctherification, sup- 

 ported by so nuich researcb in tbe foregoiug Memoir, coincides \viti» tbat 

 previously announced by Professor Grabam, in Part II. of bis Elements of 

 Ciicniistry publisbcd in 1838, by tbe following extract from tbe latter work. 

 Under tbe bead of " Circumstances tv/tich effect the order of decomposilion," the 

 alternate displacement of retber and water by eacb otber, as bases, is announced 

 and described by Mr. Grabam in tbc following terms : — 



" The remarkable decomposition of alcobol by sulphuric acid, which affords 

 ffither, is another similar illustration of decomposition depending upon volati- 

 lity, and affected by changes in tbe nature of tbe atmosphere into which eva- 

 poration takes place. Alcohol or tbe hydrate of rether is added in a gradual 

 manner to sulphuric acid somewhat diluted, and heated to 280°. In these cir- 

 cumstances, the double sulphate of sether and water is formed ; water, which 

 was previously combined as base to tbe acid, being displaced by aEthcr, and 

 evolved together with the water of the alcobol. The first effect of tbe reaction 

 therefore, is the disengagement of watery vapour, and the creation of an atmo- 

 sphere of tbat substance which tends to check its farther evolution. But the 

 existence of such an atmosphere offers a facility for the evaporation of aether, 

 which accordingly escapes from combination with the acid and continues to be 

 replaced by water, the affinity of sulphuric acid for water and for jether being 

 nearly equal, till ajtber forms such a proportion of tbe gaseous atmosphere as 

 to check its own evolution, and to favour the evolution of watery vapour. Then 

 a^ain alcobol is decomposed, and more of the double sulphate of water and 

 Ectbcr formed as at first ; the suljjbatc of rether of which comes in its turn to be 

 decomposed as before, and aether evolved. Hence, both aether and water distil 

 over in this process, the evolution of one of these bodies favouring the separa- 

 tion and disengagement of the other. In this description, the evolution of 

 water and a'ther are for the sake of perspicuity supposed to alternate, but it is 

 evident that the result of such an action will be the simultaneous evolution of 

 the two vapours in a certain constant relation to each other." p. 188. 



