1824.] the Metallic Sulphates by Hydrogen Gas. 343 



••• ••• 



ther with all its oxygen; for the weight of 2 Fe -S : Fe 4 S :: 

 0-709 : 0-420. The residue in the experiment was only a very 

 little higher, or 0-422. 



Thus to the sulphurets of iron already known, viz. Fe S 4 and 

 Fe S 4 , we can now add Fe S and Fe 4 S ; and probably that 

 series will be still further increased with Fe 2 S ; so that it will 

 be possible to exhibit a sulphate of iron, so constituted that the 

 number of atoms of the acid shall be equal to those of the base. 



Sulphate of Lead. 



The salt was decomposed by hydrogen gas with facility, and 

 sulphurous acid was disengaged, followed at last by sulphuretted 

 hydrogen. The product obtained was a mixture of sulphuret 

 -and metallic lead, which, towards the end of the process, had 

 melted together in small balls, which were quite malleable. On 

 the solution of the mass in nitric acid, a considerable portion of 

 sulphur was disengaged. 1-294 gr. of sulphate of lead pre- 

 viously exposed to a red heat, left for a residue 0*940 gr. Hence 

 it appears that a little more than half of the salt is converted 

 into metal, and the remainder into sulphuret of lead ; for the 



weight of 2 Pb S* : Pb + Pb S 3 :: 1-294 : 0-952. 



Whether in a higher temperature hydrogen gas cannot change 

 the whole sulphate of lead into metal, was not tried ; but it is 

 less probable, as we see by Berthier's experiments,* that if 

 sulphate of lead be mixed with charcoal powder, and heated in 

 a hessian crucible even to whiteness, there always remains a 

 mixture of metallic and sulphuretted lead. 



. The preceding experiments were tried also with sulphates of 

 copper, bismuth, tin, and antimony ; but none of these trials 

 gave any very remarkable results. The copper and bismuth 

 salts were reduced to pure metals. The tin salt gave metallic 

 tin still mixed with some sulphuret, and from the antimonial salt 

 was obtained a residue of oxidized metallic and sulphuretted 

 antimony. 



Article IV. 



An Analysts of some Minerals, By Aug. Arfwedson.f 



Cinnamon Stone from Mals/6. 



During a mineralogical journey in Vermlaud daring the 

 summer of 1820, Prof. BerzefiuB met with a garnet mineral in 

 the lime quarry of Masjii, in the neighbourhood of Philspstad, 



• Ann. ac Chim. July, 1822, p. 270. 



+ Translated from the Kongl. Vctcntkaps Atademiens Handlingar, for 1892, p. 87. 



