ALLOYS OF TIN. 605 



ride of tin, till the latter is saturated, which is shewn by the 

 solution ceasing to precipitate mercury from a solution of cor- 

 rosive sublimate. A solution of this salt, extensively used in 

 dyeing, and known as the nitro-muriate of tin, is generally pre- 

 pared by oxidising crystallized protochloride of tin by nitric 

 acid ; or by dissolving tin in a mixture of hydrochloric and 

 nitric acids, avoiding any considerable elevation of tempera- 

 ture. 



Bichloride of tin and ammonia, Sn C1 2 + NH 3 or (NH 3 Sn) C1 2 . 

 Anhydrous bichloride of tin absorbs ammoniacal gas, and 

 forms a white powder, which may be sublimed without decom- 

 position; after sublimation it is entirely soluble in water (Rose). 



Bichloride of tin, and phosphuretted hydrogen, 3Sn C1 2 + PH 3 . 

 These two bodies unite without the production of hydrochloric 

 acid; the compound is solid (Rose). 



Bichloride of tin and potassium, Sn C1 2 + K Cl. The solution 

 of bichloride of tin, when mixed with an equivalent quantity of 

 chloride of potassium and evaporated, yields this double salt in 

 regular octohedrons of a vitreous lustre, which are anhydrous. 



A sulphate and nitrate of peroxide of tin, have been crystal- 

 lized ; this base forms no carbonate. 



Both the sulphuret and bisulphuret of tin act as sulphur 

 acids, combining with alkaline sulphurets. The bisulphuret of 

 tin dissolves with digestion in sulphuret of sodium, and 

 the concentrated solution yields fine crystals of the salt, 

 2Na S + Sn S 2 + 12HO. The bisulphuret of tin is found 

 combined with the subsulphurets of copper and iron, forming 

 tin pyrites, a rare mineral, 2Fe 2 S, Sn S 2 + 2Cu 2 S, Sn S 2 . 



Alloys of tin. Tin alloyed with small quantities of antimony, 

 copper, and bismuth, forms the best kind of pewter, which 

 possesses the peculiar whiteness of that metal. The most 

 fusible compound of tin and bismuth, is that of an atom of 

 each metal, Bi Sn ; it melts at 289.4 (Rudberg). When the 

 metals are mixed in other ratios, a portion first congeals at a 

 higher temperature, separating from the compound mentioned, 

 which remains liquid till the temperature falls to 289.4. Al- 

 though tin precipitates copper from its solutions in acids, yet 

 it is possible to precipitate tin upon copper, and to cover the 

 latter with tin, as is proved by the tinning of pins. Tin is dis- 

 solved in a mixture of one part of bitartrate of potash, two of 

 alum, two of common salt and a certain quantity of water, and 



