other commodities, the price which is barely 
sufficient to replace, together with its ordinary 
profits, the stock which must be employed in 
bringing them to market. At a coal mine for 
which the landlord can get no rent, but which 
he must either work himself or let it alone altogether
the price of coals must generally be 
nearly about this price
Rent, even where coals afford one, has generally 
a smaller share in their price than in 
that of most other parts of the rude produce 
of land. The rent of an estate above ground, 
commonly amounts to what is supposed to be 
a third of the gross produce; and it is generally 
a rent certain and independent of the occasional 
variations in the crop. In coal mines
a fifth of the gross produce is a very great 
rent, a tenth the common rent; and it is seldom 
a rent certain, but depends upon the occasional 
variations in the produce. These are 
so great, that in a country where thirty years 
purchase is considered as a moderate price for 
the property of a landed estate, ten years purchase 
is regarded as a good price for that of 
a coal mine
The value of a coal mine to the proprietor
frequently depends as much upon its situation 
as upon its fertility. That of a metallic mine 
depends more upon its fertility, and less upon 
its situation. The coarse, and still more the 
precious metals, when separated from the ore
are so valuable, that they can generally bear 
the expense of a very long land, and of the 
most distant sea carriage. Their market is 
not confined to the countries in the neighbourhood 
of the mine, but extends to the 
whole world. The copper of Japan makes 
an article of commerce in Europe; the iron 
of Spain in that of Chili and Peru. The silver 
of Peru finds its way, not only to Europe
but from Europe to China
The price of coals in Westmoreland or 
Shropshire can have little effect on their price 
at Newcastle; and their price in the Lionnois 
can have none at all. The productions of 
such distant coal mines can never be brought 
into competition with one another. But the 
productions of the most distant metallic mines 
frequently may, and in fact commonly are. 
The price, therefore, of the coarse, and still 
more that of the precious metals, at the most 
fertile mines in the world, must necessarily 
more or less affect their price at every other 
in it. The price of copper in Japan must 
have some influence upon its price at the copper 
mines in Europe. The price of silver in 
Peru, or the quantity either of labour or of 
other goods which it will purchase there, must 
have some influence on its price, not only at 
the silver mines of Europe, but at those of 
China. After the discovery of the mines of 
Peru, the silver mines of Europe were, the 
greater part of them, abandoned. The value 
of silver was so much reduced, that their produce 
could no longer pay the expense of 
working them, or replace, with a profit, the 
food, clothes, lodging, and other necessaries 
which were consumed in that operation. This 
was the case, too, with the mines of Cuba and 
St. Domingo, and even with the ancient mines 
of Peru, after the discovery of those of Potosi
The price of every metal, at every mine
therefore, being regulated in some measure 
by its price at the most fertile mine in the 
world that is actually wrought, it can, at the 
greater part of mines, do very little more than 
pay the expense of working, and can seldom 
afford a very high rent to the landlord. Rent 
accordingly, seems at the greater part of 
mines to have but a small share in the price 
of the coarse, and a still smaller in that of the 
precious metals. Labour and profit make up 
the greater part of both. 
A sixth part of the gross produce may be 
reckoned the average rent of the tin mines of 
Cornwall, the most fertile that are known in 
the world, as we are told by the Rev. Mr
Borlace, vice-warden of the stannaries. Some, 
he says, afford more, and some do not afford 
so much. A sixth part of the gross produce 
is the rent, too, of several very fertile lead 
mines in Scotland. 
In the silver mines of Peru, we are told by 
Frezier and Ulloa, the proprietor frequently 
exacts no other acknowledgment from the undertaker 
of the mine, but that he will grind 
the ore at his mill, paying him the ordinary 
multure or price of grinding. Till 1736, indeed, 
the tax of the king of Spain amounted 
to one fifth of the standard silver, which till 
then might be considered as the real rent of 
the greater part of the silver mines of Peru
the richest which have been known in the 
world. If there had been no tax, this fifth 
would naturally have belonged to the landlord
and many mines might have been 
wrought which could not then be wrought
because they could not afford this tax. The 
tax of the duke of Cornwall upon tin is supposed 
to amount to more than five per cent. 
or one twentieth part of the value; and whatever 
may be his proportion, it would naturally, 
too, belong to the proprietor of the mine
if tin was duty free. But if you add one 
twentieth to one sixth, you will find that the 
whole average rent of the tin mines of Cornwall, 
was to the whole average rent of the silver 
mines of Peru, as thirteen to twelve. But 
the silver mines of Peru are not now able to 
pay even this low rent; and the tax upon silver 
was, in 1736, reduced from one fifth to 
one tenth. Even this tax upon silver, too, 
gives more temptation to smuggling than the 
tax of one twentieth upon tin; and smuggling 
must be much easier in the precious 
than in the bulky commodity. The tax of 
the king of Spain, accordingly, is said to be 
very ill paid, and that of the duke of Cornwall 
very well. Rent, therefore, it is probable,