190 Quarterly Abstract of European Chemistry. 



of a current of hydrogen upon it when heated nearly to redness is ex- 

 treoiely curious ; it loses all of its oxygen and part of its sulphur, leav- 

 ing a sulphuret of chrome (Cr* S'') of a blackish brown color, having 

 such an affinity for oxygen that it constitutes a very energetic pyropho- 

 rus. This sulphuret in contact with chlorine burns with energy ; in 

 contact with the vapor of water it is decomposed with a disengagement 

 of hydrogen and hydrosulphuric acid, being transformed into the oxide 

 of chrome. 



Solubility of Metals in Persulphate and PercJiloride of Iron, by 

 James Napier, (Lon. and Ed. Phil. Mag. May, 1844, p. 365.)— It has 

 been shown in the experiments upon this subject, that silver, tin, lead, 

 antimony, bismuth, cobalt, nickel, and several other metals, were solu- 

 ble in the neutral persalts of iron, reducing it to a protosalt. The per- 

 chloride of iron is proposed as a means of dissolving copper from the 

 surface of silver; the persulphate cannot be used for this purpose, as it 

 attacks readily the silver. Upon the solubility of lead in the persalts 

 of iron, Napier proposes to account for the phenomenon noticed by~ 

 Mr. West, that when spring-water, which had been running into a lead 

 tank for many years without the slightest action upon the lead, was con- 

 veyed through iron pipes to the tanks, the tanks were destroyed in six 

 years. Gold was also experimented with, but the results were doubt- 

 ful. No double salt is formed in this operation. The solubility of iron 

 in its own persalt, serves to account for the great consumption of iron 

 for the small quantity of copper obtained from the waste water of mines 

 containing the persalt, the copper never being entirely precipitated 

 from the water while any portion of it remains in solution. The iron 

 therefore has to perform a double part — converting the per into the pro- 

 tosalt of iron, and decomposing the salts of copper. 



A new series of Double Salts, by J. A. Poumarede, (Compt. Rend. 

 May, 1844, p. 854.) — Numerous combinations have been formed of 

 the sesquioxide of iron and its sulphate, with the protoxides and their 

 sulphates, the composition of the salts being expressed by this general 

 formula, ^{Fe^ O^ 3S03)-{-a;0 SO3-|-10HO. The sulphate of the prot- 

 oxides and peroxides of iron (sulphate ferroso-ferric) is formed by 

 adding two parts of the sulphate of the protoxide and two parts of the 

 sulphate of the peroxide to five or six of water ; after a few moments 

 the liquid becomes warm, and the two dissolve entirely, giving rise to 

 a clear brown solution, which affords upon evaporation crystals of the 

 salt in question. It is soluble in every proportion in water ; upon anal- 

 ysis it proves to be a neutral salt, the oxygen of the bases being to that 

 of the acids as 1 to 3. The sulphate of the peroxide of iron can be 

 combined in the same way with the sulphates of zinc and copper, 



