ANALYSIS OF SULPHATE OF BARYTES, \jg 



thus a great quantity of sulphate of lime required but little 

 water to dissolve it. Into the liquor muriate of barytes was 

 poured, and suffered to remain some time gently heated ; 

 by these means any oxalate of barytes, that might have 

 been formed, was retained in solution by the original ex- 

 cess of acid, and the entire quantity of sulphate of barytes 

 was deposited. Of the exactness of all those methods, 

 which I used as the instruments by which I ascertained 

 these results, I convinced myself by various preliminary 

 experiments. After the usual filtration, washing, and dry- 

 ing at the gentle heat of a sand bath, I obtained in one ex- 

 periment 185, in another 183, and lastly in another 180* 

 We may therefore take 183 as the mean proportion* Con- 

 sequently we shall say, 183 grains of sulphate of barytes 

 contain the same quantity of sulphuric acid, as 100 of 

 sulphate of lime (43) ; and 183 : 43 :: 100 : 23*5. There- 

 fore 23*5 are the proportion of sulphuric acid in 100 of sul- 

 phate, of barytes." 



I repeated this experiment of Mr. Chenevix with calcined Tl,,s ex P eri - 

 • *• pii i iT«tn ment repeated, 



sulphate of lime carefully prepared, and obtained from 100 



grains, as he had done, 180-5 grains of sulphate of barytes 



dried at the heat of a sand bath. Suspecting, however, 



that the various and complicated affinities, which are 



brought into play in this process, might be productive of 



some erroiir ; and that the mode was defective, though the 



results were correctly given; I dissolved 10 grains of cal- The sulphate 



cined sulphate of lime in a pint of boiling distilled water, of . lin \ e . dl * 



i . • • _,. . . solved in diy 



and poured in muriatic ot barytes. J he precipitate, washed, tilled water. 



dried, and calcined, weighed 17*7 grains. This accorded 

 so nearly with the experiment of Mr. Chenevix, that I was 

 satisfied of the exactness of his method, and that it was not 

 here I was to look for the source of the discordance. His 

 analysis of sulphate of lime I had not verified, having an 

 indistinct recollection of its agreeing nearly with the compo- 

 - sition of this salt as stated by others. On a more attentive The propor- 

 examination however I found, that the proportions, as ^R£^a 

 given by Mr. Chevenix *, are the converse of those of sulphate of 



Klaproth^'-faXr 



* Dr. Thompson, in his excellent System of Chemistry, vol. II, 

 p. 355, 2d «dition, has, by a very natural mistake in quoting from the 



W 2 Phil. 



ence. 



