ve to the different
qualities of labour, and the difficulty of comparing an hour's, or a
day's labour, in one employment, with the same duration of labour in
another. The estimation in which different qualities of labour are held,
comes soon to be adjusted in the market with sufficient precision for
all practical purposes, and depends much on the comparative skill of the
labourer, and intensity of the labour performed. The scale, when once
formed, is liable to little variation. If a day's labour of a working
jeweller be more valuable than a day's labour of a common labourer, it
has long ago been adjusted, and placed in its proper position in the
scale of value.[3]

In comparing therefore the value of the same commodity, at different
periods of time, the consideration of the comparative skill and
intensity of labour, required for that particular commodity, needs
scarcely to be attended to, as it operates equally at both periods. One
description of labour at one time is compared with the same description
of labour at another; if a tenth, a fifth, or a fourth, has been added
or taken away, an effect proportioned to the cause will be produced on
the relative value of the commodity.

If a piece of cloth be now of the value of two pieces of linen, and if,
in ten years hence, the ordinary value of a piece of cloth should be
four pieces of linen, we may safely conclude, that either more labour is
required to make the cloth, or less to make the linen, or that both
causes have operated.

As the inquiry to which I wish to draw the reader's attention, relates
to the effect of the variations in the relative value of commodities,
and not in their absolute value, it will be of little importance to
examine into the comparative degree of estimation in which the different
kinds of human labour are held. We may fairly conclude, that whatever
inequality there might originally have been in them, whatever the
ingenuity, skill, or time necessary for the acquirement of one species
of manual dexterity more than another, it continues nearly the same
from one generation to another; or at least, that the variation is very
inconsiderable from year to year, and therefore, can have little effect
for short periods on the relative value of commodities.

"The proportion between the different rates both of wages and profit in
the different employments of labour and stock, seems not to be much
affected, as has already been observed, by the riches or p