84 On dejinile Proportions. 



I.) Ten grammes of lead were dissolved in nitric acid 

 mixed with sulphuric, dried by evaporation, and ignited in 

 the flask. The sulphale weighed 14 633, and 100 parts of 

 the acid had combined with 2S0 of the oxide. 



c.) Ten grammes of oxide of lead were dissolved in nitric 

 acid, in a dish of platina, sulphuric acid was added, the 

 mixture was then dried and ignited. I obtained 13*575 gr. 

 of sulphate of lead, which gives the same proportion as 

 before. 



These three experiments, agreeing so perfectly with each 

 other, indicate a small inaccuracy in the analysis of the 

 sulphuric acid. This depends on the sublimation of a little 

 of the sulphur of the sulphuret of lead employed, leaving 

 the base of the salt somewhat redundant ; the muriatic acid, 

 which combines with this redundant portion, being ex- 

 pelled by ignition. Hence it is probable that the quantity 

 of sulphur ought not to be made greater than 40*32 for 

 100 of sulphuric acid: but in order to avoid any hypo- 

 thetical corrections, we may safely employ the first experi- 

 ment as a basis for calculation, and consider sulphuric acid 

 as consisting of 



Sulphur 40 58 lOO'OOO 



Oxygen 5942 146-427 



I must here remark, that Bucholz and Klaproth have 

 founded their determinations on the quantity of sulphate 

 of baryta afforded by a given quantity of sulphur : and as 

 there is some difference in the results of their experiments, 

 1 have thouoht it right to repeat them. 



In the carbonate of baryta, Klaproth and Rose found 

 22 parts of acid and 78 of earth; Bucholz, on the contrary, 

 never obtained more than 21 per cent, of carbonic acid. 

 The greatest difficulty is to obtain the carbonate quite pure, 

 since it is so often contaminated with iron, alkali, or sul- 

 phuric acid. I have only been able to procure it by ^irecipi- 

 talion irom the pure uncrystallized nitrate of baryta with 

 ca'bonate of ammonia. I washed the precipitate with 

 boiling water until it no longer indicated the presence of 

 baryta upon the addition of sulphuric acid ; for the car- 

 bonate of ammonia does not completely precipitate the 

 whole of the barvta, even when it is employed in excess. 

 The washed powder was strongly ignited in a dish of pla- 

 tina. 



a.) Ten grammes of this carbonate were dissf)lved in di- 

 luted sulphuric acid, the apparatus being weigh<".d, and the 

 gas caused to pass through a tube filled with muriate of 

 Time, which was also weighed. The solution was pro- 

 moted 



