ANALYSIS OF PYRITES, 357 



being then exposed to a gentle heat, as soon as no farther 

 action was produced the pyrites was completely oxided. 

 In several trials hs employed about H drachms of nitric 

 acidj and the process occupied a quarter or at most half an 

 hour. By the addition of a small quantity of water, the 

 loss that would have been occasioned, if concentrated nitric 

 acid had been employed, was avoided. 



The first specimen analysed was a grayish yellow pyrites 1st specimen of 

 perfectly crystallized in cubes. The filtered solution left 4Py''^'^** 

 grains of silex ; and muriate of barytes threw down a pre- 

 cipitate amounting to 355*5 grs. Hence Mr. Bucholz cal- 

 culates the pyrites to have contained 51-15 per cent of sul- 

 phur, estimating the sulphate of barytes to contain 32'5 of 

 acid, and sulphuric acid 42-5 of sulphur. 



The second specimen was a pyrites crystallized in cubes, 2d specimen. 

 with concave surfaces, and the edges slightly blunted, 100 

 grs. left 4'5 of silex, and formed 358 grs. of sulphate of 

 barytes. This therefore, calculating on the same data, con- 

 tained 51 '77 per cent of sulphur. 



The third was a pyrites crystallized in radii 100. grains Oid. specimen. 

 left 2 of insoluble matter, and produced 352 grs. of sul- 

 phate of barytes. Hence Mr. Bucholz calculates its sul- Mean. 

 phur at 49*G1 per cent ; and estimates the mean proportions 

 at 51 sulphur, 49 iron*, 



* If we take tjie proportion of acid in sulphate of barytes to be 

 l^^'S per cent, and that of sulphur in the sulphuric acid to be 

 43 '28 per cent ; the proportions •which Dr. Henry has adopted in 

 his Elements of Chemistry, lately published ; we shall find, that 

 the first specimen gave 5366 per cent of sulphur, the 2d 54-36, 

 and the 3d 5?'S6; the mean of which is 52-5Q to 40'-44 ot 

 irpH, €, 

 I'jtfi If ' 



•3£W bl 



Yh Description 



