20 Notices of the Labours of Continental Chemists. 



ing bisulphite of potassa with sulphur, and precipitating the 

 alkali by means of hy perchloric acid. The acid thus separated 

 is, however, not hyposulphurous but a new acid. A concen- 

 trated solution of the bisulphite is digested with flowers of 

 sulphur, but without allowing the mixture to boil ; sulphurous 

 acid is evolved, sulphuric acid generated, and the solution ac- 

 quires a yellow colour, which, however, soon vanishes. The 

 crystals which separate on cooling are dissolved in a very 

 small quantity of water and purified. The salt so obtained is 

 not decomposed by hydrochloric acid, is not changed by ex- 

 posure to the air, and when heated leaves neutral sulphate of 

 potassa : 100 parts of the salt gave 23*76 sulphurous acid, 

 1 1 -88 sulphur, and 64*36 sulphate of potassa. The constitu- 

 tion of the acid is therefore 3 S + 5 O. Langlois calls it " acide 

 hyposulfurique sulfure " (Sulpho-hyposulphurous acid). 



" The new salt crystallizes in four-sided prisms with two ter- 

 minal faces, tastes somewhat saline and bitter, is very soluble 

 in water, insoluble in alcohol ; the solution is decomposed by 

 sulphuric and nitric acids when heat is employed, sulphur and 

 sulphurous or nitrous acids are produced. Hydrochloric, 

 chloric and iodic acid are without action. Hyperchloric acid 

 isolates the new acid. It does not precipitate the salts of lime, 

 strontia, baryta, magnesia, alumina, iron, zinc, nickel, cobalt, 

 uranium, copper and lead ; from the salts of dinoxide of mer- 

 cury it precipitates the sulphuret, with salts of the oxide it gives 

 a white precipitate of sulphate of the dinoxide ; it precipitates 

 silver salts yellowish-white, which soon changes to black. 



The free acid possesses almost all the characters of hypo- 

 sulphurous acid ; it is rapidly decomposed by chloric and iodic 

 acid. — [Ann. der Chem. und Pharm., si. p. 102-110.) 



On some double Hyposulphites. 



Lenz prepared these salts by means of the hyposulphite of 

 soda, for the preparation of which Liebig proposes the follow- 

 ing method. A solution of sulphurous acid or acid sulphite 

 of soda is saturated with carbonate of soda, and a saturated 

 solution of sulphur in caustic soda added until a tinge of co- 

 lour shows that there is some sulphuret of sodium undecom- 

 posed. The filtered solution is evaporated, &c. 



The hyposulphite of soda forms two double salts with- oxide 

 of silver. They may be obtained by means of either the chlo- 

 ride or the nitrate of silver ; chloride of silver is added to a 

 saturated solution of the hyposulphite until the solution begins 

 to be opake, it is then filtered and precipitated by alcohol. 

 The precipitate, which is the one double salt soluble in water, 

 is thus obtained pure in shining scales, it is edulcorated with 



