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28th. If the vein of quartz is to be found towards the pavilion, 

 then we may be fure of the regularity and fertility of the load ; 

 for the pyrites appearing in abundance at both extremities of 

 the vein, the heart of the mountain, in which it is evident the 

 vein is fed, ought neceflarily to be very rich. 



29th. At all events, the befl; trial that can be made on that 

 place, will be to make an horizontal drift into the mountain, and 

 following the vein of quartz ; and in the courfe of this operation, 

 the bed of pyritous flate will be cut through. If the vein of 

 quartz fhall be found to be metallic, this work will turn 

 out advantageoufly ; but if it fhould not be found fo, one ought 

 then to examine whether the layers of flate, which lean againft. 

 it oppofite to the work, contain any ore. 



30th. The trial called the open caft does not appear to be 

 a regular vein ; it is a confufed heap of blueifh flate of quartz, 

 and a kind of petrofilex, through which pyrites and yellow copper 

 ore are fpread with great irregularity. That has however, towards 

 its top, an appearance of inclining in the direction of the moun- 

 tain, that is an angle of about forty-five degrees ; and it is covered 

 with a layer of quartz, which at firft looks like a vein, but 

 which, when accurately examined, is found to be nothing more 

 than a heap joined to the body of the load, and inclined like it 

 in a plane parallel to the furface. 



Vol. VIII. U 31ft. 



