--- {150} In common life, this difference, between carrying money and necessaries, is perfectly well understood, but it is experience that is the teacher; and the rough countryman, or woman, when they have the opportunity of judging from fact, understand the motives as well as the most profound and ingenius =sic= writer on political economy. -=- [end of page #182] when their industry can be both applied, with any degree of equality, to the same object, the poor supplies the rich, and therefore increases its own wealth. It is thus that great numbers of the people in London are fed with butcher-meat from Scotland, and wear shoes from Yorkshire; but there would be a very limited sale in either of those places for meat from Smithfield, or shoes manufactured in London. {151} This diminution of the value of money, that takes place in all rich countries, serves farther to increase the advantage of poorer ones in manufacturing, and accelerates the natural effect of competition, which is facilitated, as has been said, by the capital of the rich country giving activity to the industry of the poorer one. This last neither can be called an exterior nor an interior cause, as it is derived entirely from the relative situations of the two countries, and belongs to both, or originates in both; but, as it raises the poor nation nearer the level of the rich one, its effect gradually becomes less powerful. Though there is no means of preventing the operation of two nations coming nearly to a level by this means, yet it does not appear to be a necessary consequence that the nation that was the richer should become the poorer. As this, however, has been a general case, we must conclude it to be a natural one, but there we stop, and make a distinction between what is natural only, and what is a necessary effect. Their coming to a level was a necessary effect; but, though the other may be natural, it cannot be necessary, and therefore may be counteracted; to find the means of doing this, is all that is proposed by the present inquiry. --- {151} If it was not for taxes and rent, that are chiefly spent in large towns, as well as law-expenses, and the prices of luxuries, of dress, and furniture, the cities, like London, would soon be reduced. -=- [end of page #183] CHAP. XII. _Conclusion of exteror Causes.--Are seldom of much Importance, unless favoured by interior ones.--Rich Nations, with care, capable, in most Cases, of prolonging their Prosperity.--Digression on the Importance of Public Revenue, illustrated by a statistical Chart_. The exterior causes of the decline of any nation, that has risen above its level, though formidable, are nothing, in comparison to the interior causes, and are of no great effect without their co-operation.