different Earths for Carlon. 8t 



from 2 to 4 feet in thickness ; they are either called hard- 

 eeking freestone, or water-whin, or di/ke metal ; and have 

 seldom been suspected of containing iron. Almost every 

 variety I have examined has contained a portion of calca- 

 reous earth, either in the state of chalk, spar, or crystal. 

 This circumstance, added to density, leads always to a 

 strong suspicion of iron being contained in quantity. 



The ironstone subjected to the following experiments is 

 found in an irregular stratum from 4 to 8 inches thick. A 

 bed of coal is immediately below it, and a carbonaceous 

 ironstone 14 inches thick is incumbent to it. 



Its appearance is like gray freestone or sandstone, but 

 much more compact and heavy. Its surface is entirely co- 

 vered with large pjates of niica, and interspersed with calca- 

 reous earth. Its specific gravity is — 'S-4\. 



Exp. I. 400 grains of raw siliceous ironstone, 

 8 of carbon, or l-30th. 



The fusion of this mixture yielded a verv glass crystal- 

 lized in feathered radii upon tlje surface. The fracture was 

 finely prismatic, and the lustre of some of the shades un- 

 commonly luminous and deep. Towards the bottom two 

 cavities of a pearly w bite colour were found ; and imme- 

 diately below, in one similar, a melallic spherule which 

 weighed 3^ grains. Equal to 1-375 per cent, from raw 

 ironstone. 



Exp. II. 400 grains of raw ironstone, 



10 of charcoal, or l-40th. 



A complete fusion was also obtained in this experiment. 

 Tiie surface of the glass, however, in place of being shining 

 and crystallized, as in No. L, was dull, black, and covered 

 with aa enamel of oxide usual in these experiments, but of 

 an unusual thickness. The fracture was prismatic and 

 wavy, A metallic spherule was obtained which weighed 

 10-i- grains. Equal to 2-G25 per cent. 



Exp. III. 400 grains of raw ironstone, 



20 of carbon, or l-20th. 



This experiment was also completely reduced, though 

 under appearances somewhat different from No. I. and II. 

 When the cover was taken off, after redness had ceased, 

 the stirface of the glass was found semi-spherical. In half 

 a minute part of the convex was removed : at the time a 

 slight explosion was heard, accompanied with a flash of 

 ■jvarklin;^ light blue flame. Beneath, the glass was found of a 

 " iricty of browh and blue colours. Their fragment displayed 

 a dark amber considerably transparent. A neat smooth 



Vul. 21. No. 81. Feb. 1805. F skinned 



