1 14 On the Quantiijr of Sulphur 



A fecond fource of error, therefore, remaiiiefl open in this 

 branch nf the calculation, which gave the proportion of 

 23-43 of fulphiir, as that contained in 100 parts of fulphate 

 of barytes. 



However, before I would allow myfelf to call in queftion 

 fuch authorities as thofe I have quoted, I inftituted the fol- 

 lowing cxptrinients : — In a tubulated glafs retort I put 100 

 parts of purified fulphur, and poured upon them ftrong nitric 

 acid. A quilled receiver, plunging into a Woulfe's appa- 

 ratus, was adapted to the retort ; and all being well luted, 

 I proceeded to diftil. The liquor which came over was 

 poured hack fevcral times upon the fulphur, until the whole 

 was diirolved. The water which had come over, and that 

 through which the nitrous gas, produced during the opera- 

 tion, had palled, were cflfayed lor fidphureous acid, and no 

 traces of it could be found. No fulphiu- had been vola- 

 tdized, therefore no fufpicion conld remain that all was not 

 converted into fulphuric acid. The liquors which were in 

 the various parts of the apparatus were united, and to them 

 was added a fuiticient quantity of nitrate of barytes. The 

 whole was evaporated gently ; bccaufe, thouoh I am well 

 acquainted with the ve'ry little folubility of fulphate of ba- 

 rytes, I well know that nitric acid will retain a fmall portion 

 ot it, particularly when formed in a liquor where that acid 

 abounds. In a firft 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 re- 

 duced thefe quantities to 14.6 or 14.4 per cent, of fulphur 

 contained in fulphate of barytes; a difi'erence wholly to be 

 neglected. If, therefore, we lake 14.5 as the average 'for the 

 quantity of fulphur contained in 100 parts of fulpTiate of ba- 

 rytes, we fliall not be far from the truth. From the accord- 

 ance of thefe experiments, repeated and varied, I had now 

 no doubt but concerning the fource where T was to feck the 

 error, which gave 23.43 as the juft proportion. 



To afcertain this point, I operated in the following man- 

 ner: — I prepared fome lime as pure, I beUeve, as chemical 

 means can procure it. I digelied wliite marble in muriatic 

 acid; and, bv leaving an exccfs of the earth, was certain 

 that, by the fuperior affinity of lime for that acid, nothing 

 elfe had been taken up. Upon trying the lolution with am- 

 monia, no precipitate took place. By means of carbonate of 

 potafh, I feparated the lime in the Hate of carbonate; and, 

 after well wadiirjg the precipitate, expofed it in a platina 

 crucible to a violent heat, till the weight no longer dimi- 

 niflied. I am acquainted with no more efficacious method 

 4 ta 



