COMPOSITION OP BARYTIC SALTS. <JQ| 



as this disease appeared in this country, in the middle of , • 

 the 17th century, about the same time that Plater mentions 

 cretinism. The origin of both names is equally obscure ; 

 and since some of the remote causes are now discovered, 

 it is to be hoped the diseases themselves will gradually 

 disappear, and in some happier age be known only by 

 description. 



XIII. 



On the Composition of the Salts of Baryta. By t Mr. Ar- 

 thur Aikin. 



To Mr. NICHOLSON. 

 SIR, 



JL HE ascertainment of the exact composition of the salts Compositionof 

 of barytes is of such essential importance to the accuracy r ar y tic s* lt3 

 of chemical analysis, that I shall make no apology for trou- 

 bling 1 the readers of your very respectable Journal, with 

 the following details of a few experiments instituted for this 

 purpose. 



The salt selected by me as the basis of these experiments Muriate se- 



was the muriate of barytes, on account of its ready solubi- lect . e(l for ex- 



. . penraent. 



lity in water, and it*> inalterability at a red heat. I shall 



begin therefore by describing the precautions, that I took 



to ensure the perfect purity of the substance on which I was 



operating. 



Sect. 1. Preparation of pure Muriate of Barytes. 



A quantity of crystallized native carbonate of barytes Precautions t» 

 was digested in cokl and dilute muriatic acid, till all efler- ensure its P eT * 

 vescence had ceased, a portion of the carbonate remaining p '' 

 undissolved ; the solution was then filtered and crystallized 

 by rapid evaporation. The salt thus procured was ignited 

 in a platina crucible, and became of a light ochrey yellow 

 from the muriate of iron, that was decomposed. It was 

 then dissolved in cold water and filtered, by which the ox- 

 ide of iron was separated, and the liquor came through 



quite 



