A formal representation of Malthus' views on the short-run expansion and contraction of income and employment, as discussed in the Principles, has not, so far as I know, been published. Aside from any pedagogical usefulness inherent in the attempt made here to do this, it might also be worth while to examine the model with a view to its possible relevance for the contemporary scene.

Malthus' concern with effective demand produced a classification of the major categories of spending which has interesting implications for the advanced, mixed economies of our time.

It will be recalled that his flows of spending are set up somewhat as follows:

1. Consumption by the productive classes, consisting of

(a) spending for necessaries by labourers;

(b) spending for necessaries, conveniences, and luxuries by capitalists.

2. Investment spending (chiefly by capitalists), composed of

(a) circulating capital inputs, mainly necessaries contained in the wages fund;

(b) fixed capital inputs.

3. Spending by unproductive consumers, largely for conveniences, luxuries, and non-material personal services, that is, by

(a) private persons out of rentier incomes (e.g., rents and interest income on the public debt);

(b) government out of public funds raised through taxation or borrowing.

4. Foreign demand.