196 ANALYSIS OF SULPHATES OF LIME. 



IX. 



Analyfis of Natural and Artificial Anhydrous Sidphate of Lime, by 

 Rich. Chenevix, Efq. F.R.S. M.R.J, A. Communi- 

 cated by the Author. 



Component parts J/ HE proportion of the elements in common fulphate of 

 of common ful- /• i i ' o i • ... 



phateoflime. lime, fuch as I have ftated them in the Tranta&ions ot the 



Royal Irifti Academy, are fomewhat different from thofe 

 given by former chemifts. Monf. Fourcroy, in his " Syftcme 

 " des ConnoiJJances Chimiques," and in his " Synoptic Tables/' 

 has determined them in the following order: fulphuric acid 

 45, lime 32, water 22. If we deduct the quantity of water, 

 and reduce the remainder to the quintal, we fliall have the 

 following proportions : fulphuric acid 58,5, lime 41,5. As 

 the object of the prefent Paper is merely the Anhydrous ful- 

 phate, I fliall not take further notice of the quantity of water 

 that may be contained in common fulphate of lime, whether 

 natural or artificial. 

 Limediflolvedin I took one hundred parts of lime, prepared with the great - 

 and^ulphurlc e ^ care > anc * diflblved them in muriatic acid. I then poured 

 acid added, and fulphuric acid into the folution, and heated the whole in a 

 the whole ex- p} a ti n a crucible, at firft gently, but afterwards to violent ig- 

 ignition, left dry nition. The augmentation of weight in the lime and the cru- 



fulphate of hme c i D i e (which had been weighed before the operation) amount- 

 containing 56,3 l ° ; ~ 

 lime, and 43,6 ed to 78,5, and was combined lulphuric acid. This experi- 



acid. ment therefore indicates, that ftrongly calcined fulphate of 



lime is compofed of lime 56,3, and 43,6 of fulphuric acid. 



Sulphate of ba- I then took one hundred parts of calcined fulphate of lime, 



rytes contains an( j decompofed them by oxalic acid, to render them more 



24 acid in the , *, , ' • , *• . . . . .. 



100 parts. ioluble, and then dillolvea them in muriatic acid. 



I precipitated the folution by muriate of barytes, and ob- 

 tained 1 82 of fulphate of barytes. Hence it is evident that 

 182 of fulphate of barytes, and 100 of calcined fulphate of 

 lime contain the fame quantity of fulphuric acid = 43,6 ; 

 which proportion gives 24 as the quantity of fulphuric acid, 

 in 100 of fulphate of barytes. This quantity is nearly inter- 

 mediate between that given by Thenard, and that which I 

 had already ftated. By this experiment I eitablifhed a ftand- 

 ard, to which I might refer every kind of fulphate of lime. 



4 It 



