,4^ Upon ilie Preparation of pure Barytes* 



essential that it should be prepared with cirbonate of potash 

 free from sulphate ; we may render it caustic by following 

 the process published by M. Descroizilles in the Annales de 

 Chimie^, I have frequently pursued the methods he points 

 out, and I have done so with increasing advantages. i 



Observaiions ly one of the Editors of the Annales de Chimie 

 upon the foregoing Article, 



I have examined the liquor of the flask transmitted by 

 M. Darcet along with his paper. It was more than half 

 filled with small white crystalline lamince; the liquor greened 

 strongly paper coloured with the petals of mallows. I poured 

 sulphuric ajcid into it in a slight excess ; there was formed 

 an abundant precipitate of sulphate of barytes ; at no time 

 was there the least smell of acetic acid. After having fil- 

 tered the liquor in which the precipitate was formed, I eva- 

 porated it in a gentle fire in a platina crucible, and it left no 

 traceof neutral salt. There does not remain a doubt, there- 

 fore, that the acetate of barytes is radically decomposed by 

 soda.— L. B. G. 



IX. Upon the Preparation of pure Barytes. 

 By M. Roj?iciUETt« 



In a note inserted in a late number of the Annales de Chi- 

 mie X, upon the decomposition of the acetate of barytes, by 

 means of soda, M. Darcet points out as a more ceconomical 

 and more certain process of procuring pure barytes, to de- 

 compose any barytic salt, and principally the muriate, by a 

 caustic alkali : I do not think the preference he gives to this 

 process over the generally employed one, namely, the de- 

 composition of the nitrate by heat, is w«ll founded. On 

 considering the matter in an ceconomical point of view, wc 

 see that in both cases we must first oi>taia a soluble salt of 

 barytes; that in the first wc cannot employ the liquors so 



* .See Phil, Mag. vqi. x?^iii. 



f Ffom Annates de Chimie, torn, Iiii. p r>i. 



J See the preceding article, 



much 



