HEINRICH ROSE ON ^THERIFICATION. 373 



It is well known that sulphuric acid can take up more than 

 one atom of water to form a hydrate. Besides the common 

 hydrate, with one atom of water, we are acquainted with a 

 second, which may be prepared in a crystalline state, and con- 

 tains two atoms of Avater. This combination coiTesponds to a 

 basic sulphate salt. 



The disposition of the hydrate of sulphuric acid to take up 

 more water is very great, and it is employed on this account 

 for various purposes in our laboratories. It is this which pre- 

 vents theeether, originating from the decomposition of the sulpho- 

 vinic acid, from taking up the second atom of water ; but if the 

 ii 'mixture is uninterruptedly boiled for some time, the hydrated 

 i sulphuric acid loses the acquired water, which may then be 

 i[ distilled over in company wdth the aether. The aether therefore 

 t may be distilled over at the same time with water, from a boil- 

 }: ing mixture of the hydrate of sulphuric acid and alcohol ; but 

 they are not the products of one, but of two chemical pro- 

 ; cesses, which are both active together in the boihng mixture. 



At the commencement of the operation but very little w^ater 

 i passes over along with the aether and that alcohol contained in 

 i the mixture, which has not been converted into sulphovinic acid, 

 so that the water remains dissolved in the distilled alcoholic 

 .-ether, and does not separate : the quantity of water increases 

 by further distillation, especially at a high temperatm*e, Mhen 

 the quantity of the second hydrate of sulphuric acid has 

 augmented. 



Alcohol is scarcely ever employed anhydrous in the prepara- 

 tion of aether, but generally hydrated. It is evident that in the 

 i latter case the quantity of the second hydrate of sulphuric acid 

 I must be considerably increased. The experiments of Liebig, 

 I Magnus, and Marchand have shown that in the cold this 

 I second hydrate cannot form sulphovinic acid with alcohol, but 

 i does so at a higher temperature, and therefore that such a mix- 

 iture on boiling can give aether by distillation. But it is well 

 IknowTi that on emplojang hydrated, or even anhydrous alcohol, 

 there is always a portion of it w^hich is not converted into sul- 

 phovinic acid, and this quantity may be distilled as alcohol 

 from the mixture. A second portion of alcohol, which distils 

 over in company with the aether, in the formation of aether, 

 may, however, be produced in this way, — that aether and water 

 are cotemporaneously disengaged from the mixture, and com- 



