26'2 PHILOSOPHICAL TRANSACTIONS. [ANNO 1782. 



within the bell to a height equal to 87.2 cubic inches; whence I deduce that 

 87.2 cubic inches of fixed air were produced, which contain 7.287 gr. of phlo- 

 giston, which separated from the vitriolic acid, and united to the dephlogisticated 

 part of the common air under the bell. The candle of sulphur being weighed, 

 was found to have lost 20.75 gr. ; therefore, 20.75 gr. of sulphur contain 7.287 

 gr. of phlogiston, besides the quantity of phlogiston which remained in the 

 vitriolic air. This air must have amounted to 20.75 — 7.287 = 13.463 gr. 

 which contain 1.141 gr. of phlogiston ; therefore the whole quantity of phlo- 

 giston in 20.75 gr. of sulphur, is 8.428 gr. ; therefore, 100 gr. of sulphur con- 

 tain 40.6l gr. of phlogiston and 59.39 of vitriolic acid. 



Several attempts have hitherto been made to determine the proportion of the 

 constituent parts of sulphur ; but all were evidently defective. The first was 

 that of Stahl, who calculated the quantity of phlogiston from that of the acid 

 remaining after slow combustion ; but as much, both of acid and phlogiston, 

 was dissipated, and as the remaining acid was also phlogisticated, and attracted 

 much of the moisture of the air, no conclusion whatever could be drawn from 

 this experiment. The 2d method was, to form a liver of sulphur, and convert 

 this by a gentle long continued heat into a tartar vitriolate, and then calculate 

 the weight a given quantity of alkali would gain by this operation. This was 

 also devised by Stahl, and followed by Brandt and Newman, and by it they de- 

 termined the proportion of phlogiston to that of acid to be nearly as 1 to 16. 

 But during the formation of the liver of sulphur, whether in the moist or dry 

 way, much of the phlogiston and acid is dissipated, as is evident by the vapour 

 and smell that proceed from it, their alkali also contained fixed air, which it lost 

 during the operation, and of which they kept no account, as they were ignorant 

 of its existence ; and the tartar vitriol formed by them or sal polycreste retained 

 much undecomposed sulphur, as always happens when it is not strongly heated ; 

 so that this method also was very imperfect : however some subsequent chemists, 

 who made the experiment with more care, concluded from it, that sulphur con- 

 tained 4- of phlogiston. Exleben, §760. 



By weighing flowers of sulphur in a perforated brass box in water, J found its 

 specific gravity to be I.924. It remained in the water a quarter of an hour be- 

 fore any air issued from it, and then some bubbles arose ; but when I opened the 

 box, I found the middle part of the flowers quite dry, so that I make no doubt 

 but some air still remained, and that its specific gravity is still greater. Mr. 

 Petit weighed it in oil, aud found its specific gravity 2.344, which I believe to 

 be nearly the truth. 



Of the quantity of phlogiston in marine acid air. — 8 gr. of copper dissolved in 

 colourless spirit of salt, afforded but 4.9 cubic inches of air, when the air was 

 received over water, and this air was inflammable. 8.5 gr. of copper being dis- 



