OF THE ASBESTINE EARTH. 



certainly no one, from the character of a (lone, 

 foft, fibrous, and flexible, would be led to ap- 

 prehend fuch an abundance of filiccous matter. 



In the conipnfitioh of the nine fpeeics, reckon- 

 ed, with the confent of all mineralogifts, under 

 the name of aibelli, which have hitherto been 

 chemically examined, the filiceous earth is found 

 to conllitutc the greater part, making never lefs 

 than the half, and fometiiiies three fourths of 

 the whole. In relation to quantity, magnefia 

 holds the fecond place between the limits of 

 iz.y and 28.8 in the centenary. Then follows 

 the aerated chalk, fluctuating from 6.0 to 14.3. 

 Argillaceous earth is in the fmall proportion of 

 1.6 in the centenary. Calcined iron is found 

 in all of them from 0.9 to 10.6. The fpecific 

 difference therefore fccms to be thus determin- 

 ed: 



AJl>eJlos compofcd of filiccous, magncfian, 

 calcareous, and argillaceous earth, with fomc 

 admixture of ferruginous matter. Metallic fub- 

 itances arc indeed extraneous ; but, as earths 

 of the purcft kind arc fcldom entirely free from 

 iron, it mull ftill be confidercd as a fpccics of 

 alloy. In this order the materials of the com- 

 poiition being enumerated, according to their fc- 

 veral proportions, illuftratc clearly the fpecific 

 diflercnces. 



As to what relates to thofe fubflanccs that 

 bear different degrees of rcfemblance to the af- 



beiti, 



