22 Historical Sketch of Improvements in [July, 



and alcohol, but extends to other acids, and to many vegetable 



substances. 



These experiments of Sertlirner have been repeated and con- 

 firmed by M. Vogel, of Munich, at least so far as the vmion of 

 sulphuric acid and alcohol is concerned. He extracted the acid, 

 conibined it with different bases, and showed that the new acid 

 of Sertlirner possessed exactly the characters of hyposulphuric 

 acid, with this difference, that it always holds in combination a 

 pecuhar oily matter, which somewhat modifies its properties, 

 (Jour, de Phann. vi. I). 



M. Vogel concludes from his experiments, that the theory of 

 etherification advanced a good many years ago by Fourcroy and 

 Vauquelin, is inaccurate ; and that the objections started against 

 that theory by M. Dabit, of Nantes, were well founded. M. 

 Dabit actually formed the acid pointed out by Sertlirner, and 

 described several of the salts which it forms. 



These important experiments of Vogel have been repeated and 

 confirmed by Gay-T.ussac (see Ann. de Chim. et de Phys. xiii. 

 62), wlio prepared sulphovinate of barytes {su/p/iovliiic acid is 

 the provisional name given to this acid by Vogel) in a state of 

 purity, and subjected the acid to analysis. It crystallizes in fine 

 rhomboidal prisms, terminated by four-sided pyramids, the faces 

 of which correspond with those of the prism. They are transpa- 

 rent, and do not alter in the open air ; but become opaque when 

 kept under an exhausted receiver along with sulphuric acid : 100 

 parts of this salt dried in the air when calcined lost 46"07 parts, 

 and furnished 54"93 parts of sulphate of barytes. The same 

 quantity of salt calcined with chlorate and carbonate of potash, 

 and afterwards precipitated by muriate of barytes, yielded 111*47 

 parts of sulphate of barytes, or nearly double what was obtained 

 in the first experiment. Thus it appears that the acid possesses 

 exactly the constituents and the capacity of saturation of hypo- 

 sulphuric acid, and that the vegetable matter which it holds in 

 combination produces no alteration in these particulars. 



This curious subject deserves much fuller investigation than it 

 has hitherto met with. Sertlirner, though his experiments were 

 far from precise, and his opinions very vague, has had the merit 

 of drawing the attention of chemists to the action of sulphuric 

 acid on alcohol, which was undoubtedly entitled to a much more 

 accurate investigation than it has hitherto obtained. It was this 

 that induced me to insert a translation of his paper in the Annals 

 of' P/ii/usoplii/. 



4. Action of ]\'irric Acid on Uric Acid. — When uric acid is 

 dissolved in nitric acid, and the solution set aside for some time, 

 transparent crystals are deposited, to which Brugnatelh, who 

 first attended to these crystals, has given the name of erythric 

 acid. The nature of these crystals has not hitherto been exa- 

 mined ; nor do we know whether they be entitled to rank as a 

 peculiar acid. 



