208 On the Muriate of Tin. 



a silky mass of crystals of muriate of tin. If we purify 

 the crystals of muriate of tin by solutions in pure water 

 and by crystallization they assume more consistence and 

 more density. 



The crystallized muriate of tin is very" soluble in cold 

 water; the solution lakes place verv speedily,' and produces 

 a considerable decrease of temperature. The mean decrease 

 of temperature in the experiments which I made was 9° of 

 Reaumur, the temperature of the atmosphere and that of the 

 substances employed being 5 Q . The mixture of the mother 

 waters and of pure water produces no change of temperature. 

 As I had observed that these mother waters became a 

 little fuming on being concentrated, I tried to distil both 

 the highly concentrated mother waters and crystallized 

 muriate, to see if I could not obtain a muriate of tin similar 

 to that which was known by the denomination of fuming 

 liquor of Libavius : I obtained at first a weak muriatic acid, 

 and afterwards the muriate passed into the receiver, where 

 it was sublimed into the neck of the retort in a white mass 

 formerly known by the name of butter of tin. With the 

 same view I passed muriatic acid gas as dry as possible 

 through the concentrated mother water of muriate of tin : 

 it became fuming, and gave crystals on its mixture with 

 pure water. JBufl ought to observe that the fuming li- 

 quor of Libavius exhales vapours much thicker and more 

 abundant, the whiter and the denser it is. 



The combinations of muriatic acid and tin in the state 

 of solution, of crystals and of mother water, are always 

 effected with an excess of ,acid ; and we see from what has 

 been said, that all of them are susceptible of infinite varia- 

 tions in their state. We must not be astonished, therefore, 

 if the results which they produce in dyeing are so uncertain 

 and so different from each other. The least variable state 

 of muriate of tin seems to be that of very while and well- 

 formed crystals. It is in this state that this mordant ought 

 always to be employed in dyeing, by associating it with a 

 greater or less quantity of pure nitric acid, according to 

 the shade which we wish to obtain : such a composition 

 can alone be always uniform and give constant results. 



By taking advantage of the facts contained in this me- 

 moir, it would he easy to describe a simple and advantageous 

 process for preparing on a large scale the muriate of tin in 

 crystals : I have nevertheless met with some very embarrass- 

 ing difficulties in the execution, which I have succeeded in 

 removing; and the full description of my labours will be 

 given in a subsequent memoir, 



XXXVIII. The 



