Sulphur and Phosphorus, 41 i 



If, according to Mr. Dalton's ideas of proportion, the 

 quantity in which sulphur enters into its combinations were 

 to be deduced from its union with potassium, in which it 

 seems to form about one- fourth the weight of the com- 

 pound, the number representing it would be"^3*5. I have 

 lately weighed sulphuretted hydrogen and sulphureous acid 

 gas, with great care : the specific gravity of the first at mean 

 temperature and pressure, from my experiments, is 106*45, 

 which differs very little from the estimation of Mr. Kirwan : 

 that of sulphureous acid gas I find is COQ67- Sulphuretted 

 hydrogen, as I have shown, contains an equal volume of 

 hydrogen; and on this datum the number representing sul- 

 phur is 13*4. I have, never been able to burn sulphur in 

 oxygen without forming sulphuric acid in small quantities; 

 but in several experiments I have obtained from 02 to 98 

 parts of sulphureous acid from 100 of oxygen in volume ; 

 from which I am inclined to believe, that sulphureous acid 

 consists of sulphur dissolved in an equal volume of oxvgcn ; 

 which would give the number as 13-/ * nearly, considering 

 the acid gas as containing one proportion of sulphur, and 

 two of oxygen; and these estimations do not differ from 

 each other materially. 



I have made several experiments on the combustion of 

 phosphorus in oxygen gas. From the most accurate, I am 

 inclined to conclude that 25 of phosphorus absorb in com- 

 bustion about 34 of oxygen in weight : and considering 

 phosphoric acid as composed of three proportions of oxy- 

 gen and one of phosphorus, the number representing phos- 

 phorus will be about lG'5, which is not very remote from 

 the number that may be deduced from the composition of 

 phosphuret of potassium. 



The numbers which represent the proportions in which 

 lulphur and phosphorus unite with other bodies, are such, 

 as do not exclude the existence of combined portions of 

 oxygen and hydrogen in their constitution ; hut it may be 

 questioned, whether the opinion which I formed, that the 



* The estimation from the composition of sulphuretted hydrogen, must 

 be considered as most accurate, and that from the formation of the suJphurct 

 of potassium as least accurate: for it was only by combining sulphur and 

 potassium in small proportions, and ascertaining in what cases uncombined 

 sulphur could be distilled from the compound, that I gained my conclusions 

 concerning the composition of the sulphuret of potassium. 



In the last Bakerian lecture, I have estimated the specific gravity of sul- 

 phuretted hydrogen at 35 grains the ICO cubical inches, which was not far 

 from the mean between the estimations of Mr. Kirwan and Mr. TI, 

 According to this last experiment, sulphuretted hydrogen is composed of 

 one proportion of hydrogen, represented by 1, and one of sulphur rep; e- 

 «cnted by 13 4. 



inflami. 



