290 Sulphuric Acid. 



M. Thenard makes it to consist of 74*82 of barytes and 

 25*18 of sulphuric acid. 



M. Chenevix says it contains 76*50 of barytes and 23*50 

 of sulphuric acid . 



M. Kirwan gives 67*00 of barytes and 33*00 of sulphuric 

 acid as its proportions. 



M. Richter gives 69*00 of barytes and 31*00 of sul- 

 phuric acid. 



And, finally, M. Bucholz says it is composed of 67*00 

 of barytes and 33*00 of sulphuric acid. 



Thus we see that if we except the analyses of Messrs. 

 Chenevix and Thenard, all the rest have a great resem- 

 blance to each other ; and if we take the medium, that 

 of Kirwan is the truest, which induced M. Klaproth to 

 adopt it. 



It is here necessary to explain the means employed by 

 M. Klaproth in his researches : he introduced into a re- 

 tort 200 grains of pure sulphur, and eight ounces of pure 

 nitric acid, of the specific gravity of 1*320. He distilled 

 until about three fourths had passed into the receiver. 

 What came over was poured back into the retort, and 

 was again distilled ; he afterwards added eight ounces of 

 acid, and distilled the whole. 



M. Klaproth found that the unburnt sulphur weighed 

 48 grains and a half; he therefore had 151 converted into 

 sulphuric acid. 



The produce diluted in a certain quantity of water was 

 mixed with muriate of barytes, until there was no longer 

 any precipitate produced in the liquor. The sulphate of 

 barytes well washed and dried weighed 1109 grains, but 

 when calcined in a platina crucible, its weight was re- 

 duced to 1082 grains. 



In order to ascertain the proportion of the constituent 

 principles of the concrete sulphuric acid, M. Klaproth 

 took 100 grains of very strongly concentrated sulphuric 

 acid, of the specific gravity of 1*850 ; he diluted in in 15 

 parts of water, and poured in muriate of barytes until no 

 more precipitate was formed. The sulphate of barytes 

 carefully washed and dried weighed 225 grains. From 

 these facts it results, 



1st, That 100 parts of sulphuric acid of the specific gra- 

 vity of 1*850, are composed of 74*04 of concrete acid and 

 2506 of water ; or, of 31*05 of sulphur, 42*09 of oxygen, 

 and 25*06 of water. 



2d, That 100 parts of concrete acid are formed of 

 42*03 of sulphur and 57*07 of oxygen. 



3d, That 100 parts of calcined sulphate of barytes con- 

 tain of barytes 67*00, sulphur 14*00, and oxygen 19*00. 



XLVII. Prin- 



