[ m ] 



eflayed for fulphureous acid, and no traces of it could be- found.. 

 No fulphur had been volatilized; therefore no fufpicion could 

 remain, that all was not converted into fulpbcric acid. The- 

 liquors, wTiich weje in the various .parts of the apparatus, w-ere 

 united; and to them was added a fufficient quantity of nitrate 

 of Barytes. The vyboie vi^as evaporated gently; becaufe, though 

 I am well acquainted with the very little folubility of fulphate 

 of Rarytes,, I well know that nitric acid will retain a fniall. 

 portion of it, particularly v»hen formed in a liquor where that 

 acid abounds. In a firfl experiment, I obtained- 694. from 100 

 of fulphur, in a fecond, 348 from 50, and in a third, 347, 

 from the fame quantity. But the fimple rule of three reduced 

 thefe quantities to 14,6, or 14.4 per cent, of fulphur, contained' 

 in fulphate of Barytes ; a difference wholly to be negleded. If, 

 therefore we take 14.5 as the average, for the quantity of 

 fulphur. contained in 100 parts of fulphate of Barytes, we fhall,- 

 not be far from the truth. From the accordance of thefe ex- 

 periments, repeated and varied, I had now no doubt, but con- 

 cerning the fource where I was to feek the error, which 

 gav€ 23.43 as the juft proportion. 



To afcertain' this point, I operated in the following manner:: 

 I prepared fome lime, as pure, I believe, as chymical means 

 can procure it. I digefted white marble in muriatic acid; and, 

 ^OL. VIII. Gg by 



