ANALYSIS OF SULPHATE OF 8ARYTES. 177 



water. It is here our experiments chiefly disagree ; but 

 the difference does not amount to one per cent, and more 

 perfect accordance will hardly be expected by those, who 

 are in the habit of making such experiments. 



Sulphate of Earytes. 



One hundred grains of carbonate of barytes were dis- Muriatic soliu 

 solved in muriatic acid* in a platina crucible, and preci- j^"/^ ^ 

 pitated by sulphuric acid. After slow and careful evapo- ph uric acid, 

 ration to dryness, the crucible was exposed to a white heat 

 during half an hour, and afterwards weighed. The cal- 

 cined sulphate of barytes amounted to 116*8 grains. 



2. One hundred grains of nitrate of barytes were de- Nitrate of ba- 

 composed by solution of sulphate of soda added in excess, * ^ b . su j # 

 and the mixture gently heated. The precipitate well phate of soda. 

 washed, dried, and calcined, weighed 88*6 grains. 



Now 100 grains of carbonate of barytes contain 78*25 Composition 

 grains of barytes, and produce 116.8 grains of calcined of the sul * 

 sulphate of barytes ; , P 1 * 



Aud 100 grains of nitrate of barytes, containing 5§'3 

 grains of barytes, produce 88*G of sulphate; 



From which it follows, that sulphate of barytes is com- 

 posed of 



Sulphuric acid • • • » 33*04 

 Barytes • • * 66-96 



100 



The results of the preceding experiments, every one of The ca«se of 

 which was carefully repeated three or four times, and their merit between 

 perfect accordance with those of Withering, Klaproth, and eminent chy- 

 others I have already quoted, left no doubt of their accu- miS S ° 

 racy on my mind. 



Aware however, that no individual authority, however 

 respectable, can add to or detract from the confidence 

 which the names of Thenard, Berthollet, and Chenevix 

 inspire; and sensible that my single testimony added to 

 the rest would weigh but little in the scale against them ; 

 I was desirous, if possible, of detecting the source of this 

 discordance in their experiments, as the surest and only 



Vol. XXI II.— .July IS09. N means 



