for a year, is the
result of two concurrent elements or factors,--viz., 1st, the quantity
of commodities which the state of the labour market affords to him;
2ndly, the cost of production of each of those commodities. It follows,
that the rate of profits can never rise but in conjunction with one or
other of two changes,--1st, a diminished remuneration of the labourer;
or, 2ndly, an improvement in production, or an extension of commerce, by
which any of the articles habitually consumed by the labourer may be
obtained at smaller cost. (If the improvement be in any article which is
not consumed by the labourer, it merely lowers the price of that article,
and thereby benefits capitalists and all other people so far as they are
consumers of that particular article, and may be said to increase gross
profit, but not the rate of profit.)

So, on the other hand, the rate of profit cannot fall, unless
concurrently with one of two events: 1st, an improvement in the
labourer's condition; or, 2ndly, an increased difficulty of producing
or importing some article which the labourer habitually consumes. The
progress of population and cultivation has a tendency to lower profits
through the latter of these two channels, owing to the well known law
of the application of capital to land, that a double capital does not
_caeteris paribus_ yield a double produce. There is, therefore, a
tendency in the rate of profits to fall with the progress of society.
But there is also an antagonist tendency of profits to rise, by the
successive introduction of improvements in agriculture, and in the
production of those manufactured articles which the labourers consume.
Supposing, therefore, that the actual comforts of the labourer remain
the same, profits will fall or rise, according as population, or
improvements in the production of food and other necessaries, advance
fastest.

The rate of profits, therefore, tends to _fall_ from the following
causes:--1. An increase of capital beyond population, producing
increased competition for labour; 2. An increase of population,
occasioning a demand for an increased quantity of food, which must be
produced at a greater cost. The rate of profits tends to _rise_ from
the following causes:--1. An increase of population beyond capital,
producing increased competition for employment; 2. Improvements
producing increased cheapness of necessaries, and other articles
habitually consumed by the labourer.

*