different Earths for Carlson. ' 83 



dcmble portion of the mixed formed a kind of infusible 

 carburate, which always betokens an excess of calcareous 

 earth. 



Recapitulation of the Experiments with raw siliceous 

 Ironstone. 



per cent. 

 Exp. I. l-50th carbon yielded of metal d^r grs. or 1*375 



II. I -40th ditto 10^ or 2-625 



III. l-20th ditto 17 or 4-250 



IV. l-ioth ditto 32 or 8 



V. 1-1 0th & 140 grs. chalk 70 or 17-1. 



VI, l-8th yielded ditto 96 or 24* 

 VII. l-7ih fusion became imperfect both with 



md without the addition of calcareous earth. 



The same ironstone was found to lose 28-^ per cent, in 

 roasting. Its colour was now changed to brownish red ; 

 the mica had assumed several prismatic shades, and resem- 

 bled small metallic plates tarnished by a slight degree of 

 oxygenation. The following are the results of experiments 

 made with the ironstone in this state upon 400 grains of 

 matter. 



Exp. I. l-50th carbon yielded no metal. 



II. l-40th ditto ditto percent. 



III. ]-30th ditto 7 grains of metal, or 1*75 



IV. l-20th ditto 19 ditto 4-75 

 V. ]-10th ditto 43 ditto 10*75 



VI. l-8th ditto 72 ditto '18* 



VII. l-5th ditto infusible. 



VJII. l-8lhchalkl50ditto II9 grs. of metal, or 29*75 



IX. l-5th ditto infusible. 



From a review and comparison of these experiments, 

 made with the natural productions of our mines and similar 

 compounds artificially compared, we may perceive a very 

 strict analogy. The following abstract or table may be 

 compared with one in the List vjlumc of this work, 

 p. 137. 



F a Table 



