384 llEIXUICn ROSE ox .ETlIEniFICATIOV. 



tion of nether from mixtures of phosphoric and arsenic acids with 

 alcohol. For the present, however, I leave it undecided whe- 

 ther the formation of aether, by treating alcohol with fluo- 

 boraclc gas, as also with the chloride of zinc and other chlo- 

 rides, is to be explained by a mere subtraction of water by 

 these substances ; or in this way, that they form with alcohol, 

 at the common temperature, combinations analogous to sulpho- 

 vinic acid, which are decomposed like it, at a high temperature, 

 by the agency of water. The latter view I regaid as being the 

 most probable. 



Postscript*. 



In the preceding Memoir 1 have compared the formation of 

 aither from a mixture of sulphuric acid and alcohol, with the 

 decomposition of several inorganic salts by means of water ; I 

 have endeavoured to show that it is the water Avhich in these 

 cases acts the part of a base, and separates the oxide of aethyl 

 or the metallic oxide, the latter generally as basic salt. 



The inorganic salts which I enumerated in this comparison 

 as examples, were those of the oxide of bismuth, the oxide of 

 mercury, and of antimony. These undergo the said decompo- 

 sition by water even at the common temperature ; ajther, how- 

 ever, is first separated from a mixture of sulphuric acid and al- 

 cohol, or from sulphovinic acid, at a high temperature. 



There are, however, among the inorganic weak bases, a con- 

 siderable number Mhich are eliminated by water, from their 

 combinations with acids only at a high temperature; and the 

 decomposition of the salts of these bases, by means of water, is 

 therefore still more fit to be compared to the formation of aether. 



To these bases belongs more especially the peroxide of iron, 

 which is precipitated by water as basic salt from solutions of 

 most of its neutral salts at a high temperature. The weaker 

 the solution of the salt of peroxide of iron, the lower is the tem- 

 perature which occasions pi'ecipitation, and the more completely 



* Tlip present Postscript appeared in the following part of Poggendorff's 

 Annalei), und°r the title " On the precipitation of some metallic oxides by 

 water." 



