different Earths for Carton* 341 



VI T. 300 grains of Sturbridge clay* 

 200 — k — * of oxide* 



This mixture was fused into a rough mass without any 

 appearance of glass or vitrification. It was carefully ex- 

 amined, but not one particle of metal could be found re- 

 vived. 



VIII. This was Exp. IV* repeated with the addition of 

 80 grains of raw chalk. The result was a very perfect fu- 

 sion. The glass was of a dark olive green colour, and co- 

 vered a very neat metallic button, which was found to weigh 

 1 14 grains, equal to 22-^ths per cent. This additional pro- 

 duce of 8 ,Vhs percent, above what was obtained in Exp. IV* 

 and the perfect fusion of the mixture, may be solely attri- 

 buted to the addition of 80 grains of chalk. From which 

 it may be justly inferred, that although calcareous earth 

 does not appear to absorb carbon itself, yet it acts a part 

 not less important or interesting, by facilitating the union 

 of the metallic particles with the carbonaceous matter in the 

 mixture, and thus enlarging under the same circumstance 

 the metallic produce. 



IX. This experiment was performed with the same pro- 

 portion and quantity of mixture as Exp. I ; only vitrified 

 Sturbridge clay was put in place of the same clay in a raw 

 State. The result was a very neat metallic spherule of iron 

 which weighed 1 2 grains; equal to 2-^ths per cent. The ex- 

 periment which more immediately corresponds with this is 

 Exp. I; the result of which gave 2 T tt ff ths per cent. The diffe- 

 rence of -A-ths per cent, is so small, that nothing certain can 

 be inferred from the use of clay in two states so opposite 

 to each other. 



A very different result, however, takes place when Wedge- 

 wood 's pyrometric clay is used in the mixture. 



X. Wedgewood's clay - - 300 grains* 

 Oxide x - 200 

 Charcoal - - - 12-J 



The result was a neat spherule of malleable iron which 

 weighed 1 1 grains ; equal to 2-,-^ths per cent. This expe- 

 riment was repeated, and a similar shaped spherule of iron 

 obtained which weighed 14 grains ; equal to 2 T B ths per cent. 

 These results are nearly the same with Experiments I and 

 IX, where Sturbridge clay was used. 



XI. Wedgewood's clay, vitrified in 



a heat of 1 70°* - - 300 grains. 



Oxide - - 200 



Charcoal - - - 12^- 



Vol. 19. No. 76. Sept. 1804. A a The 



