2 1 6 NATURAL HISTORY 
dians. Should not therefore all uncommon ores near thefe places be 
well examined, not only by wafhing, but by the more ceitain cri te- 
nons of quickfilver, fire, and the hydroftatic balance ? Our dreamers 
know indeed native gold, but gold is not always apparent to the 
eye ; fometimes it is found in brooks, as in Larecaja in Amer lean 
Spain k , in colour and fhape like fmall fhot (the ore being fmoothed 
and rounded by the agitation of water as our tin-grains) ; of theie 
they melt away the outward coat, and then the granules are or a 
red colour : Sometimes gold is found in the clefts of rocks , o: 
a grey colour on the ou tilde like unto lead : Sometimes the ore of 
gold well powdered muft be tried and coheded by quickfilver, cr 
great lofs will enfue, and the gold be wafhed away. Again : Gold 
is often found mixed and incorporated with other metals ; with 
copper often, with filver ftill oftner, and fometimes inferted in tin 
cryftals, but moftly bedded in diverfe forts of ftones m , and fome- 
times to the depth of one hundred and fifty fathoms. 
It may be worth while therefore for people to acquaint themfelves 
with thefe different appearances of this moft precious metal ; and 
fince we are convinced by thefe late difcoveries, that we have more 
gold in Cornwall than was ever formerly imagined, it may reafona- 
bly be fufpeded, that in our Copper and tin, in the ftate of ore, 
and for want of a proper commixture of quickfilver, a great deal 
more efcapes us than we coiled:. Laftly, in working the mines of 
thofe hills in St. Stephen’s, St. Meuan, and St. Eue, for which there is 
fuch apparent encouragement, careful and intelligent perfons fhould be 
appointed to fuperintend the bottoms ; befides, the brooks and rivers, 
which run from thofe hills, might probably pay well for fearching. 
sect. iv. Before I finifh this treatife of metals, I cannot but take notice 
Mountains that feme learned men, obferving moft mines to be on rifing grounds, 
tothTpro- 17 have thence concluded that mountains were necefiary to the pro- 
duction of dudion of metals 5 and Mr. Ray (Creat. page 216) doubts whe- 
ther there can be any generation (as he calls it) of metals and 
minerals in perfedly plain and level countries ; with fubmifiion, 
there is very little reafon for this doubt. A mountain, quatenus 
fuch, has no more to do with generating minerals than a valley ; it 
cannot be owing to its fhooting up into the air that it becomes me- 
tallic ; the unevennefs of the outward furface of the earth can have no 
effed this way : if there be any generation, it muft be owdng to the 
concurring materials contained in the bowels of the mountain, mate- 
rials as well fpread in the loweft valleys ( though perhaps fomewhat 
deeper immerfed) as in the higheft hills, and as apt to unite and 
form a body of ore in the one as in the other : in fhort, metals are 
k Al. Barba, page 74. 
1 In Coroico, ibid. 
m Ibid, 
difpofed 
