On the Muriate of Tin. 207 



when the bell-glass is filled with pure oxygen gas. In order 

 to facilitate the combination of the oxygen gas with this re- 

 cent solution, I made to pass through it a great quantity of 

 atmospheric air, by means of a pair of bellows, the pipe of 

 which goes to the bottom of the liquor. When it is not 

 sufficiently saturated with tin, it takes a new portion of it 

 in proportion as it absorbs the oxygen from the atmosphere. 

 The oxygenated muriatic acid gas is absorbed by this so- 

 lution with great energy, as Pelletier has very aptly observed. 

 He had even proposed the solution thus saturated with ox- 

 ygenized muriatic acid gas for dyeing scarlet. J requested se- 

 veral artists to try it, but none or them adopted it. It should 

 seem that the combination of atmospheric oxygen 2;ives it 

 nearly the same properties with those of oxygenized muri- 

 atic acid gas. When it has absorbed much of the oxyge- 

 nized muriatic acid gas, it becomes proper for dissolving a 

 new quantity of tin ; and as soon as it has dissolved it, again 

 its state becomes changed, having become capable of ab- 

 sorbing more oxygen. 



The muriatic solution of tin at 45° of density gives upon 

 evaporation crystals of muriate of tin. The crystallization 

 takes place the more easily the less recent the solution is, 

 or the greater the quantity of oxygen which the solution 

 has absorbed.' The mother water, which swims above the 

 crystals, is of a very great density, particularly after several 

 crystallizations. The density is still more considerable, if 

 we set it to evaporate before exposing it to the air. It is 

 even sometimes slightly smoking, and may then furnish 

 crystals by diluting it with pure water. A flask containing 

 14 parts of distilled water, contained 28 parts of mother wa- 

 ter coming from the first crystals. The same flask con- 

 tained 31 parts, when this same liquor had given by con- 

 centration several layers of crystals. These mother waters 

 are capable of being combined with the oxygen of the at- 

 mosphere, when the solution has not been previously satu- 

 rated with it. It is sufficient to expose them to the air, or 

 jto act with a pair of bellows, as already pointed out with re- 

 gard to the simple solution. This combination produces 

 more crystals ; and if the exposure of the mother waters to 

 the air takes place over a very great surface, we obtain a 

 muriate of tin crystallized in very thin and slight scales 

 Baume had observed this last method of crystallizing. The 

 oxygenized muriatic gas is combined with the mother wa- 

 ters with a good deal of energy, a considerable quantity of 

 caloric is extricated, and after cooling, the liquor goes into 



a silkv 



