Mr. J. Wilson's Remrclus into the Alum Manufacture. 417 



Per cent. 

 BaO SO 3 10-76 . . . 5-93 sulphur. 



10-57 . . . 5-87 



11-02 . . . 6-08 

 Average 5-94 



To determine carbon and hydrogen, the dried shale was burned 

 with chromate of lead, with the proper precautions. 



Per cent. 

 16-65 grs. gave 2-42 CO 2 . . . 3-96 carbon. 



1-60 HO . . . 1-06 hydrogen. 

 14-51 grs. gave 2-13 CO 2 . . . 4-00 carbon. 



1-41 HO ... 1-08 hydrogen. 



Carbon. Hydrogen. 

 Average . . . 3-98 1-07 



The total iron present in the shale is 8-09 per cent., and 5-94 

 per cent, of sulphur require 5*19 of iron to form bisulphide with 

 it. Deducting 5-19 from 8'09, we have 2-90 per cent, iron, or 

 3'72 per cent, protoxide uncombined with sulphur. The nitrogen 

 was obtained by combustion with soda lime, and precipitation 

 by bichloride of platinum, 17'83 grs. giving — 



Platinum '76= '62 per cent, nitrogen. 



I also found potash in small quantity. 200 grs. of shale gave 

 •78 KC1 = -24 per cent. KO. 



The complete analysis will stand thus : — 



Silica 4828 



Alumina 26 - 90 



Protoxide of iron 3-~2 



Lime 2-38 



Magnesia trace 



Potash -24 



Bisulphide of iron 11-13 



Water 202 



Carbon 3-98 



Hydrogen 1*07 



Nitrogen -62 



100-4 



This shale lies in seams which vary in thickness from a few 

 inches to about three feet and a half. It underlies the limestone, 

 and is deposited above the coal. It is very hard as it comes from 

 the mine, but soon decomposes when exposed to the air. Some- 



Phil. Mag. S. 4. Vol. 9. No. 01. June 1855. 2 E 



