Capital, Volume Three: The Process of Capitalist Production as a Whole by Karl Marx

"In England there takes place a steady accumulation of additional wealth, which has a tendency ultimately to assume the form of money. Now next in urgency, perhaps, to the desire to acquire money, is the wish to part with it again for some species of investment that shall yield either interest or profit; for money itself, as money, yields neither. Unless, therefore, concurrently with this ceaseless influx of surplus-capital, there is a gradual and sufficient extension of the field for its employment, we must be subject to periodical accumulations of money seeking investment, of more or less volume, according to the movement of events. For a long series of years, the grand absorbent of the surplus wealth of England was our public debt As soon as in 1816 the debt reached its maximum, and operated no longer as an absorbent, a sum of at least seven-and-twenty million per annum was necessarily driven to seek other channels of investment. What was more, various return payments of capital were made. Enterprises which entail a large capital and create an opening from time to time for the excess of unemployed capital. are absolutely necessary, at least in our country, so as to take care of the periodical accumulations of the superfluous wealth of society, which is unable to find room in the usual fields of application." (The Currency Theory Reviewed, London, 1845, pp. 32-34.)

Of 1845 the same work says: