208 NATURAL HISTORY 
a copper lode that will produce fuch a furprizing quantity or copper, 
and in Cornwall, where we have fo much water ulually in the bot- 
toms of our mines, the cupreous particles may in many places be 
too much diluted to yield the above-mentioned great return, but it 
is not to be queftioned that the experiment will anfwer, under 
proper directions, in a great many adits, efpecially where one drift 
or adit ferves as a drain to many workings. 
Another point worthy of confideration is this ; “ that copper 
grows in the fame places with gold and filver, and oftentimes, in 
following a vein of pure copper, they have met with a neft of the 
fineft gold ; but it is more ufual to have its veins change into filver \ 
« The mine of Ofloquee, in the Lipes of Peru, was at the top in a 
manner all copper, and every fpade’s depth, as they dug downwards, 
the ore grew more rich in filver, untill in the bottom it became all 
pure filver s ,” and in a copper-mine called Huel-cock, in the pariffi 
of St. Juft, native filver has been found among the copper ore, and 
it would be very wonderful if this mine fhould be the only one 
which afforded an inftance of this kind among fuch a number of 
mines as we have, and fome much richer than this. 
That the glafiy red has a great affinity to the filver ores has been 
mentioned before, and it is not improbable but fome of our ores 
may contain gold as well as filver. Copper-mines have alfb quick- 
filver oftentimes in their lodes, and in Hungary it is thought ftrange 
when the Herenground mines are ever without it. Now in Cornwallthe 
proprietors, generally fpeaking, do not know the quality of the plaineft 
copper, much lefs the nature of the richeft : they take the word, as well 
as the money of the buyer implicitly ; nor are they at liberty, by 
the prefent rules of commerce, to infift upon any afiay they have 
made of their own ores, or poftpone the fale to a better offer. This 
matter might poffibly be put upon a more fatisfadory as well as 
equitable footing, in cafe an affay-office was eftablifhed for every 
owner to have recourfe to, and afcertain in fome degree the value of 
his ore before he treats with the agents of the company ; but better 
ftill, and more likely would it be to bring the ore to a juft value, 
if melting-houfes were ereded for refining copper in the fame man- 
ner as there are for tin. This would employ an additional number 
of hands, and every new employ is of fervice to the county in pro- 
portion to the number employed : this would alfo leave the feller 
at liberty to frequent that melting-houfe which offered moft kindly 
for his ore. It is objected, that the expence of importing coals 
from Wales for melting copper, will never permit fuch a icheme 
to take place. Whether this be matter of fad or not, is at prefent 
1 Sir Hum. Mackworth of the mines, page 151. s Alonfo Barba, page 8 v. 
kinder 
