366 Mcount ofih» Origin of thtArt 



getable and animal matters on which the concentrated culphurie 

 acid exerts an action at a moderate temperature, and without 

 manifesting sulphurous acid, on being treated by that acid, gave 

 birth to hypo-sulphuric acid combined with a vegetable or ani- 

 mal matter, which appears in general different for each kind 

 of substance. Ought we accordingly to distinguish as many 

 particular acids as there are vegetable or animal matters com- 

 bined with hypo- sulphuric acid ? We think not: but it would 

 be premature to attach at present too much importance to this 

 opinion. 



The theory of etherification as it has been given by Fourcroy 

 and Vauquelin can no longer be maintained. Sulphuric acid really 

 yields oxygen to alcohol, and the result of the etherification ap- 

 pears to be ether, hypo-sulphuric acid, and a vegetable matter 

 of an oily nature, which has the greatest analogy to mild spirit of 

 wine. It forms in fact a considerable quantity of hypo-sulphuric 

 acid, relatively to the ether produced, and the spirit of wine doe* 

 not manifest itself, except at the same time with the sulphurous 

 acid — that is to say, that these two bodies are the result of the 

 decomposition of sulphovinous acid. The alcohol, to change itself 

 into ether, only requires to abandon hydrogen and oxygen in the 

 proportions in which these bodies enter into the composition of 

 water; but since the sulphuric acid really yields oxygen, it should 

 separate from the charcoal, and it is in the spirit of wine we 

 ought to find it again. 



It is very probable, according to these new facts, that in the 

 bitter of Welter, and other analogous compounds, the acid is in 

 the state of nitrous acid. 



The investigations which we have made are still too imper- 

 fect to be much insisted on, arid we should even have deferred 

 making them known had it not been for the opportunity furnished 

 us bv those of MM. Dabit, Sertuerner and Vogel. 



LXI. Account of the Origin of the Art of manufacturing Tifi' 

 Plate. By Samuel Parkes, F.L.S.* 



JboRMERLy none of the EngHsh workers in iron or tin had any 

 knowledge whatrver of the methods by which this useful article 

 could be produced ; our ancestors, from time immemorial, having 

 supplied themselves with it from Bohemia and Saxony. The 

 establishment of this manufacture in those districts was doubt- 



• From A descriptive Account of the several Processes which are usually 

 pursued in the Manufacture of the Article known in Commerce by the Name 

 of Tin-Plate, inserted in Vol. III. of the Mcinoire of the Literary and Philo- 

 sophical Society of Manchester. 



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