The latter part of the same book will treat of the exterior causes of decline, arising from the envy of other nations; their advancement in the same arts to which the nations that are rich owe their wealth, or their excelling them in other arts, by which they can be rivalled, reduced, or subdued. After having inquired into external and internal causes; and the operation of each and of both, (though they never act quite separately,) accidental causes, will make an object for consideration, which will bring the general inquiry to a conclusion. The third book will begin with an application of the information obtained to the present state of England: by comparing its situation with that of nations that were great; and, by endeavouring to point out a means by which its decline may be prevented. Though we know that, in this world, nothing is eternal, particularly in the institutions of man; yet, by a sort of fiction in language, when the final term is not fixed, and the end desirable, what is known to be [end of page #6] temporary is considered as perpetual. Thus, the contract between the king and the people, the constituent laws of a country, &c. are considered as permanent and of eternal duration. In this case, though the final decline of a nation cannot be prevented; though the nature of things will either, by that regular chain of causes which admits of being traced, or by their regular operation of coincident causes which is termed accidental, sooner or later put an end to the prosperity of every nation, yet we shall not speak of prolonging prosperity, but of preventing decline, just as if it were never to happen at any period. Before entering upon this Inquiry, it may be well, for the sake of being explicitly understood, to define what I mean by wealthy and powerful nations. In speaking of nations, wealth and power are sometimes related to each other, as cause and effect. Sometimes there is between a mutual action and re-action. In the natural or ordinary course of things, they are, at first, intimately connected and dependent on each other, till, at last, this connection lessening by degrees, and they even act in opposite directions; when wealth undermines and destroys power, but power never destroys wealth. {10} Though wealth and power are often found united, they are sometimes found separated. Wealth is altogether a real possession; power is comparative. Thus, a nation may be wealthy in itself, though unconnected with any other nation; but its power can only be estimated by a comparison with that of other nations. Wealth consists in having abundance of whatever mankind want or desire; and if there were but one nation on earth, it might be wealthy; but it would, in that case, be impossible to measure its power. Wealth is, however, not altogether real; it is in a certain degree comparative, whereas power is altogether comparative. The Romans, for example, may very justly be called the most