I02 New Procefs for maMng 



In the courfe of making the ferles of experiments from 

 which the foregoing are felcdled, I had occafion to remark 

 that the mixture of argil and carbonate, when moderate pro- 

 portions were ufed, entered into fufion in lo to 15 minutes 

 from ihe period of being introduced irtto the furnace, and 

 from 15 to 20 minutes before the iron meUed. A few cru- 

 cibles were withdrawn at this early llageof the procefsj the 

 glafs was found porfeAly pure and tranfparent. The pieces 

 of ron were more or lefs welded tooether, but poflelfed tlieir 

 original fliape and quality. And though it tn:iv feem fome- 

 ■what foreign to the prefent fubjeft, 1 (liall further remark, 

 that fo long as the pieces of iron remained unfufed or fufing, 

 a continual bubbling took place upon the furface of the liquid 

 glafs refembling the difcharge of an claftic body. I foon 

 learned to prejudge the degree of perfe6lion in the fufion by 

 the furface of the glafs. In imperfe^S rcdntlions this was 

 completely covered with various fized bubbles, manv of 

 which were concentric : on the contrary, when the metallic 

 button was found poffefTed of fmoolhncrs and uniform denfitv, 

 the furface of the glafs was either entirely fmooth, or at motl 

 prefented one folitary bubble exactly in the centre, through 

 which it is prefumable, at the time of its fixing, had been 

 difcharging the laft portions of the gaieous fubftance for- 

 merly alluded to. 



In purfuing the inveftigation of this fubjeft, I had pre- 

 pared a variety of other experiments, The fufion of the 

 fame Swedifli iron with deacidified carbonate and argil, in 

 various degrees of mixture, and with the former alone, 

 formed a diftin6l head. The fimilarity 01' die relults, ex- 

 cepting an alteration in the colour of the glafi!es, renders 

 thefe experiments no longer inlerefting. Ofhers, however, 

 performed with Britifh cold fliort iron, made in the ilamping 

 procefs, are more worthy of notice. 



Various weights of iron were fufed with mixtures of argil 

 and carbonate, and with the latter alone. In every cafe, a 

 much greater quantity of metal difappeared than in any of 

 the former experiments, and a fimilar difterence in the ap- 

 pearance of the glafs. 



ift, In twc experiments performed with cold fliort iron 

 and an equal mixture of i-3d each of Kilkenny marble and 

 Stourbridge clay (old pot) in the one, and double the weights 

 of the iron of each in the other, the lofs of metal was —th 



and —th : average, — — . The accompanying glafs was pof- 



feflt'd of an uncommon degree of luftre and denfity. Its frac- 

 ture prefented a polifli and colour fuperior to black marble : 



very 



