French National Ihsiitule. 153 



This mern')ir, more precious on account of the new che- 

 mical methods which it has sjggcstetl than by its tlirect 

 resiiUs, also contains several interesting remarks ; and 

 among others this pirticular one, that vapours are heavier 

 in proportion as the liquids they are produced from are 

 more volatile. 



The theory of sulphuric ether formerly given by Fourcory 

 and Vau(|uelin is therefore confirmed in this respect, that 

 the acid forms no part of the composiiion of this liquid. 



But this is not the case with respect to ethers formed by 

 the action of the volatile acids upon alcohol : the acid enters 

 into the combmation. either completely formed, or by nieans 

 of its elements. M. Thenard had proved (his Jast year, with 

 respect to the nitric elher. He afterwards extended his in- 

 quiries to the muriatic and acetic ethers, and showed that 

 acid is to be met with in thetn, either from the effects of 

 time or of combustion, although it is in these cases so well 

 disguised, that neither the alkalis nor the other known re- 

 agents do sjeparate it from them at their first formation. 

 In these case"?. Does it exist in an entire state, or decom- 

 posed in its eientents? This question is of difficult solution, 

 notwithstanding its interesting nature, so far as the muriatic 

 acid is in question. iVI. Boulay, however, having succeeded 

 after an interval of time in absorliing the muriatic ether by 

 ammonia, and having distinctly and separately extracted al- 

 cohol and muriate of ammonia, thinks that the acid and 

 the alcohol were simply combined together ; and he extends 

 this conclusion to the nitric and acetic ethers. 



M. Boulay has also succeeded in preparing phnspltoric 

 ether, the theory of which brmgs us back to that of the 

 feulphuric elher. 



M. Vauquelin continues his important analysis of the 

 <li'fferent kinds of iron, and his inquiries into the ingredients 

 which occasion the bad qualities of some of them. 



One kind of iron, which broke when hot in the hands of 

 6ome workmen, w^ile in the hands of others it was passable, 

 only yielded one six-hundredtli part of phospiiorus, and a 

 tour hundredth part of chrome. Another kind of iron which 

 crumbled under the hammer at a white heat, and which pre- 

 sented a grain like that of steel, without its hardness, con- 

 tained one three-hundredth part of arsenic and one hun- 

 dredth part of phosphorus. 



M Vauquelin is at present occupied with inquiring by 

 what nie.ins we may free iron from prjt)cipk;s of which 

 $uch a small quantity alters the uoulity uf the ntctal. 



M.Cav- 



