The second case of doubt was merely one of expediency—whether free trade should be introduced quickly or slowly. “In what manner the natural system of perfect liberty and justice ought gradually to be restored” Smith left to the wisdom of future statesmen and legislators to determine. But he maintained that the evils attending the remedy were usually exaggerated, and this view proved to be correct when Sir Robert Peel and Mr. Gladstone effected the transformation by five mighty strokes of the fiscal axe. We have now examined all the passages which could give colour to the impression that Smith was only a free trader—on conditions. That part of the task is easy enough. The difficulty begins when we seek positive arguments against protective or differential taxation. The woodman of Mount Ida was not more embarrassed in choosing a tree to fell. The _Wealth of Nations_ is a forest of full-grown arguments for free trade. The more one reads it, the more irresistibly is one driven to the conclusion that the science of political economy, as established in this masterpiece, is inextricably bound up with the doctrine of free trade. Every assumption and conclusion, his criticisms of previous and existing theories, laws, customs, and opinions, his surveys of the commercial and colonial policy of Europe, all bear us directly or indirectly to the same goal. Yet there is one principle which seems to take precedence in the argument. In the division of labour, Smith found a key to the growth of wealth and to the enlargement of the material comforts that are necessary to the progress of refinement and civilisation. The division of labour is therefore his starting-point, and instead of leaving it where Plato and Aristotle let it rest—a barren formula of economic society—he sets it vigorously in motion, and converts it, as it were, from a slumbering lake into a vast reservoir that irrigates and fertilises the whole plain of inquiry. And had he been confined to one argument for free trade, this is probably the one he would have adopted. If we were asked to select that passage in the _Wealth of Nations_ which gives most succinctly the broad objections to a protective policy, we should turn to the second chapter of the fourth book, “Of restraints upon the importation from foreign countries of such goods as can be produced at home.” He begins by admitting that high duties or prohibitions can secure to home producers a monopoly of the home market. At that time British graziers enjoyed the monopoly of providing the home market with butcher-meat. The manufacturers of wool and silk were equally favoured, and the duties on foreign linen, for which Hume had pleaded in one of his commercial essays, had lately been raised.