It may be worth while remarking that his illustrious contemporary Malthus remained more or less of a Protectionist.[356] It might seem strange that Malthus, continually haunted as he was by the spectre of famine, should refuse to welcome importation. But his point of view was doubtless largely that of the modern agricultural Protectionist, who believes that the surest way of preserving a country from famine is not to abandon its agriculture to the throes of foreign competition, but, on the contrary, to strengthen and develop the home industry by securing it a sufficiently high price for its products. We must also remember that Malthus’s theory of rent differed somewhat from Ricardo’s, and that he was not so violently opposed to State intervention.[357] But Ricardo’s principal contribution to the science was his discovery of the laws governing the movements of commodities and the counter-movements of money from one place to another, and the admirable demonstration which he has given us of this remarkable ebb and flow. As soon as the balance of commerce becomes unfavourable to France, let us say—that is, as soon as importation exceeds exportation say by £1,000,000—money is exported to pay for this excessive importation. Money becomes scarce, its value rises, and prices fall. But a fall in price will check foreign importation and will encourage exportation, so that imports will show signs of falling off while exports will grow. Money will no longer be sent abroad, and the current will begin to run the other way, until the £1,000,000 sent abroad is returned again. Moreover, the £1,000,000 sent abroad will cause a movement in the opposite direction—superabundance and a depreciation in the value of money, high prices, a premium on importation and a check upon exportation. Accordingly economic forces on both sides will conspire to bring back the balance of commerce to a position of equilibrium—that is, to that position where each country will possess just the quantity of money that it needs. It might be pointed out, on the other hand, that this somewhat complicated mechanism can only operate very slowly, and that considerable time must elapse before the prices of goods begin to respond to the change in the quantity of money. But as a matter of fact it is not necessary to wait until this phenomenon becomes established, for another striking feature precedes it and announces its approach so to speak, and this is, as Smith had already noted, a change in the value of bills drawn on foreign countries. The foreign exchanges are so sensitive that the slightest rise is enough to stimulate exportation and to check importation.