ANALYSIS OP SULPHATES OF LIME. 157 



It is evident that calcined fulphate of lime, or artificial an- 

 hydrous fulphate of lime, contains 43,6 of fulphuric acid. It 

 remains to prove its chemical identity, with the natural an- 

 hydrous fulphate. 



I took one hundred parts of this fubftance, in as pure a The natural an- 

 nate as the Count de Bournon could procure it, and fubmit j£?™\J^ phate 

 ted it to the fame experiments. I obtained from this experi- treated like the 



ment 187 of fulphate of barytes, which announces 44 88. I artificial, and. 

 y. n ./,-.. r gave 44> 8 8 acid, 



inall never expect more uniform remits m two analyies, even 



of the fame fubftance, and do not hetitate to pronounce, that 



the two fulphates are, chemically fpeaking, one and the fame 



thing. 



The Abb6 Hauy in his late work has given the proportions Vauquelin's ex- 



in anhydrous fulphate of lime, according to an analyfis of P er, ™ ents S 3 ^ 

 i/r r rr i- r™ • „ , -o r , . t much more acid j 



Mom. Vauquehn. This excellent chemift found its elements 



to be nearly in the inverfe order of my ftatement, and fuch as 

 Fourcroy has eftablifhed them for the artificial fulphate, de- 

 ducting the water of cryftallization. I fliould ftill have doubted 

 the accuracy of my experiments, if I had not difcovered a 

 caufe that may explain the difference which exifts between 

 his refults and mine. 



The French chemifts have mentioned two varieties of ful- mod probably 

 phate of barytes, one of which contains 13 per cent, of ful- f~™ high^*" 

 phuric acid, and the other 35. If therefore we eftimate the proportion of 

 quantity of acid contained in fulphate of lime, by the fulphate ^atiofb^te's. 

 of barytes containing 33, and not by that containing 24 per 

 cent, we (hall have a much greater quantity of fulphuric acid, 

 as a conftituent part of fulphate of lime. 



Among the fpecimens which the Count de Bournon gave Some fpecimens 

 me for trial, there were fome which contained muriate of ° f the anh y- 

 foda. This fait was eafily extracted by water alone ; and the contained muri- 

 proportion of it differed in different fpecimens. Klaproth had ate or "f° da » 

 fome fpecimens in which he found carbonate of lime, and 

 even filica. But as I have examined fome in which I can po- but it was acci- 

 fitively affert that there was neither the one nor the other, dental * 

 thofe fubftances may be looked upon as merely accidental. 



X. Abridgment 



