of the Pyrites; 7.9 



have been duly funk, or dug for, without finding 

 any thing of that fort. In the famous fand-ftone 

 quarry, at Pirna, in Mifnia, the common ore- 

 depth has not been hitherto reached; and what 

 pity is it, that fo extraordinary a quarry mould 

 not be more carefully examined ? The loam-beds, 

 likewife, have equally partaken of the fame fate ; 

 namely, to lie neglected and unexamined. 



Now, tho' our experience, which is, hitherto, 

 inconfiderable enough, fhould fuffice to give the 

 preference to the Jhiver, above other Jlream-beds y 

 in regard to the pyrites- Jquats, yet it would be no 

 difficult matter to find out fome reafon for this 

 difference; namely, thofe parts proper for the 

 mixtion of pyrites , as the fat earth for the -fulphur, 

 and the tender earth for the iron, as has been al- 

 ready mentioned, are found, efpecially the firft in 

 the fhiver, not only proximately prepared for the 

 pyrites^ but alfq indifputably in greater plenty than 

 in loam and fand : and the matrix is not to be 

 confidered as a bare receptacle, but as a receptacle 

 of proper materials too ; that is, the inhalations, 

 or impregnations, called inweatherings y cannot 

 alone have their effect, nor their fupplying then- 

 materials produce an ore, unlefs the matrix hold, 

 and reciprocally furnifh alfo, by means of an ex- 

 halation, called outweathering, its proper matter; 

 that the paffive may, by means of the agent, come 

 into motion, to form the third body here intend- 

 ed. In loam, 'tis true, a fat earth is contained, 

 from which iron may be, and actually is produced 5 

 but naturally not in fuch quantity, as that the iron 

 fhould put on the form of a pyrites^ and it is the 

 fame with a body over-dofed with fulphur. In 

 the fand-ltone the parts of the whole have too far 

 deviated from the nature of an earth, and arrived 

 at fuch a degree of hardnefs, to be incapable of a 

 greater remove from the form of an earth, from 



which 



