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2dly. The decompofed part neverthelefs weighed after decotn- 

 pofition only 360 grains, 



3dly, 300 grains of vitriolated tartarin were alfo obtained. 



In this experiment we are only to attend to the 428 grs. which 

 were decompofed, as the 52 that efcaped decompofition were no 

 way altered. 



In the firft place it is plain that the 428 grains that were de- 

 compofed contained at leafl as much vitriolic acid as they im- 

 parted to the alkali in forming 300 grains of vitriolated tartarin : 

 Now*3oo grains of vitriolated tartarin contain 45 x 3 = 135 of 

 real vitriolic acid therefore 4:8 grains of barofelenite contain 

 at leaft 135 of real vitriolic acid, that is, 31,5 per cent, a quan- 

 tity that already approaches pretty nearly to the direft refults of 

 moft analylls. But in the next place it is equally evident, that 

 the quantity of acid was greater than here ftated, and the quan- 

 tity of mere barytic earth much below 360 grains, the quantity 

 exprefled in the 2d refult ; for if this quantity were juft, the fum 

 of its weight and of that of the acid would furpafs the weight 

 of the decompofed part. As inliead of 428 the fum would 

 amount to 360 + 135 = 49 51 which is impoifible. The truth 

 then is, thatthofe 360 grains of refiduary earth conaprehend the 

 weight not only of the mere earth, but alfo of the fixed air, 

 which it had taken from the alkali in exchange for the acid it had 



impE 



rted 



