359 
Mr. Taylor on the Smelting of Tin Ores , &c. 
Mine Tin is, as I have mentioned, the produce of veins, and is 
raised with a mixture of all the substances which unusually accom- 
pany it. There are, not unfrequently, copper ores, pyrites, wolfram, 
micaceous iron, &c. and the separation of these, as also of the 
earthy matrix, is the object of various processes of dressing, which 
are conducted with the greatest care, and require a considerable 
portion of labour. 
Whether, in a country where fuel for smelting is on the whole 
very cheap, it might not be economical to diminish the labour of 
dressing, and by leaving more to be done in the furnace, reduce 
the expense of the former operations, is a question that I have 
never submitted to a direct experiment, though I conceive it to be 
one worthy of trial. The various earths may be quickly separated 
by fusion, as in the case of copper ores, which are now always 
smelted with a large mixture of the different kinds of spar in which 
they are found, all of which is easily run off by the fire, and the 
scoria or slag separated from the metallic part. 
The fusibility of tin offers a mode by which it may be separated 
from an alloy of most other metals with which it is found to exist 
in veins, as lead and zinc ores are seldom mixed with it. This 
property is now made use of to a certain extent in refining tin, 
and might probably be taken advantage of still further, so as to 
avoid some of the charges incurred in dressing the ore. 
The metal produced from Mine Tin is always of inferior quality, 
owing to the mixture of other metals, and which it is probable 
could not by any mode be entirely got rid of; it is known in 
commerce by the name of Common or Block Tin, and the quantity 
forms a large proportion of the whole that is brought to market. 
Stream Tin is found in the lowest stratum of alluvial matter, in 
the bottoms of deep vallies, or places where a considerable deposit 
Vol. V. 2 z 
