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XXXVII. Memoir on the Muriate of Tin. By M. Be- 

 raid, Ex~ Projector of Chemistry in Mmtpellier. 



-L he preparation on a large scale of muriate of tin has fur- 

 nished me w ith the opportunity of observing some interest- 

 ing facts. They will serve as appendages to those which 

 have been described by various writers, and perhaps may 

 tend to accelerate the discovery of an uniform and certain 

 method of preparing and using the composition for dyeing 

 scat let, which is a kind of salt of tin. 



The solution of tin by the muriatic acid, as described by- 

 various authors, and as practised by Baume, is operated 

 by pouring on one part of the metal in a state of very mi- 

 nute division, lour parts of common muriatic acid, and as- 

 sisting the chemical action by the heat of a Band-batb. The' 

 water, which serves as a vehicle to the acid, is decomposed, 

 the oxygen oxidizes the metal, which is then combined with 

 the acid, while the hydrogen is liberated in the gaseous state, 

 carrying off with it some particles of the metal employed, 

 which render it very fetid. But the action is slow, and the 

 solution is effected in an imperfect manner. I observed 

 that a verv great part of the acid employed was evaporated 

 and lost ; and that if we wished to operate the entire solu- 

 tion of the metal, we must not only add acid in the place of 

 that which was evaporated, but also keep up the action by 

 heat for several days. I tried to perform this operation in 

 the cold way, and two months were insufficient. Bayer and 

 Charlard, in their inquiries upon tin, employed six months 

 in the operation. , r 



M. Chaptal assists the chemical action between the mu- 

 riatic acid and the tin, by placing, when he has prepared this 

 ,acid,the metal in the vessels ofWoolPs apparatus, m which 

 was the water which might to receive the vapours. The 

 heat which is extricated produces the best effect, and the 

 action becomes very brisk towards the end of the operation. 

 But *his ingenious contrivance still leaves something to be 

 desired, in so far as the acid only dissolves the fourth of its 

 weight of tin, and. we must terminate the solution by other 

 means. 



We may operate the solution of tin still better by receiv- 

 ing into a large receiver, in \\ hich we have introduced a suf- 

 ficient quantity of the metal in minute division, the vapours 

 of muriatic acid, which are liberated from a mixture of mu- 

 riate of soda in powder and of sulphuric acid weakened to 

 the 40th degree of Baume's areometer. On operating a 



simple 



