ON HIDROGURETTED SULPHURET OF BARYTES. £5 



the expense. And as to the purity of the product, since the 

 washing must be performed very sparingly, I do not see, 

 that the process of Mr. d'Arcet deserves the preference in 

 this respect: for it is probable, that the barytes thus ob- 

 tained will retain a little of the salt of the mother water J 

 and on the contrary that obtained from the nitrate is ex- 

 tremely pure, at least if the precaution be taken, before it is 

 decomposed, to calcine it slightly, and redissolve it, in or- 

 der to separate a portion of iron proceeding from the suU 

 phate employed. 



VIII. 



Remark on the spontaneous Decomposition of the kidroguret* 

 ted Sulphuret of Barytes : by Messrs. Robiquet and 

 Chevreul*. 



JL N the course of last month, Mr. Robiquet, in order to se- Two sorts of 

 parate some crystals, that had formed in a phial half filled ^^neo^y 

 ivith hidroguretted sulphuret of barytes, turned it upside in hidroguret- 

 down, without uncorking it. Some days after, the weather ^ farv\e&. 

 having grown colder, the liquor afforded some tolerably large 

 crystals, which were of a very different figure from those, 

 that remained at the bottom of the phial. We have exa- 

 mined these two substances together, and the following are 

 the results of our observations. 



1. The first crystals were elongated prisms. On the ap- 1st, sulphuret 

 plication of sulphuric acid they gave out sulphurous acid ' etl f lu P h ^ °£ 

 gas, and at the same time let fall sulphur mixed with sul- 

 phate of barytes, Hence there could be no doubt, that.they 



were sulphuretted sulphite of barytes. 



2, The mother water, in which the second crystals had 2d, pure b^ 

 formed, was colourless and very limpid. It retained nei- Jy^'watei 

 ther sulphur nor sulphurous acid ; had all the characters of 



a simple solution of barytes in water; and the crystals com- 

 ported themselves as the crystals of that earth. They dis- 

 solved in weak muriatic acid without effervescence, and rn 



# Annales de Chimie, yq\. LX1I, p. 180, Mar, 1807. 



watep 



