13 
__ “Tt is by the known occurrence of this stream tin that the lodes are usually 
detected. The method of working would be to follow up a lode thus accidentally 
laid bare, and to work inwards until reaching an alvine course which always 
determines the line of the main passages. 
**When tin stone has been raised from the lode it is first subjected to stamping, 
by which it is reduced to the consistency of fine sand. The separation of tin 
from sand depends on the fact alluded to just now, that when grit is mixed 
with water, as in a muddy river, the heavier particles are dropped first. From 
the stamps the sand is washed away by a current of water, proceeding along 
channels cut for it on a slight incline for some 30 or 40 yards. By repeating 
this process, at last nearly pure ore is found in the bed of the channel. 
‘*Next the ore is subjected to a heat so great that arsenic, sulphur, and other 
substances often occurring as impurities in the tin volatize and disappear. The 
tin ore is then in a marketable form. To reduce it to metallic tin, it is heated 
in a restricted current of air, after being intimately mixed with finely divided 
carbon. The oxygen now leaves the tin and unites with the carbon to form 
carbonic acid, the tin being left in the metallic form.” 
The writer here described his descent into Botallack. 
“T cannot now detain you with a special description of the copper mines. 
That metal is found exclusively in clay-slate, and often in company with tin, 
as in the Botallack mine to which I have just referred. I lay specimens on 
the table, and you will notice that many of them are of great beauty, being of 
the variety known as fcacock copper. 
“I wish, however, to say 2 few words about the mine from which I obtained 
the sections hanging on the wall. It is situated in a most beautiful spot on the 
sea-shore, close to Tintagel, (a name replete with very different associations,) 
and in fact undermining the ruins of the castle which legends assign to King 
Arthur. Here we have an instance of a mine yielding silver, lead, and some 
copper, the silver appearing as an alloy in the lead, and amounting in some 
samples to as much as 20 ozs. silver to the ton of lead. 
“The method by which so small a quantity of silver can be profitably 
separated from the lead deserves notice, as it is one of those beautiful applications 
of the more recondite laws of nature to man’s use. The law here made use of 
is that a substance in crystallizing tends to reject all foreign bodies. Thus lead 
in crystallizing tends to separate from its crystals the silver mixed with it. To 
apply this principle a row of earthen pots are immersed in hot cinders, some of 
the alloy being placed in the middle pot. The lead, on partially cooling, 
= to crystallize; the crystals are skimmed off and placed in a pot to the 
t, the fluid from the bottom being placed in the pot to the left. The same 
process is repeated at each of the pots; and, in consequence, in the pots to the 
right ye lead is becoming continually more and more pure, in those to the left 
more and more largely alloyed with silver, so that in the one the most to the 
left there will be lead with a large percentage of silver, amounting perhaps to 
one or two per cent. The lead can now be reduced to lithage or oxide of lead 
ting in a current of air, the silver sinking to the bottom in the form of 
metallic beads. 
“Tn conclusion, it may please the fancy to trace back the dawn of the 
commercial greatness of this country to these same Cornish tin mines. They 
seem to have been the only tin mines known to the ancients, and from them 
was probably obtained the tin for their bronze statues. Indeed Diodorus 
Siculus, writing in 9 B.c., speaks thus of the trade of the ancients with Britain : 
The inhabitants of Belerium are hospitable, and, on account of their intercourse 
‘with strangers, civilized in their habits. It is they who produce tin, which 
‘they melt in the form of knuckle-bones, and carry to an island in front of 
*Britain, called Ictis. The island is left dry at low tides, and they then 
“transport the tin in carts from the shore. Here the traders buy it of the 
