It is a great assistance to memory, now and then to assemble our ideas, after certain intervals, in going through an extensive subject. No part of it can be treated of with distinctness, without banishing combinations; and no part of it can be applied to practice, or adapted to any plan, without attending to combinations almost infinite. For this reason nothing can appear more inconsistent than the spirit which runs through some parts of this book, if compared with that which prevailed in the first. _There_ luxury was looked on with a favourable eye, and every augmentation of superfluity was considered as a method of advancing population. We were then employed in drawing mankind, as it were, out of a state of idleness, in order to increase their numbers, and engage them to cultivate the earth. We had no occasion to divide them into societies having separate interests, because the principles we treated of were common to all. We therefore considered the industrious, who are the providers, and the luxurious, who are the consumers, as children of the same family, and as being under the care of the same father. We are now engaged in a more complex operation; we represent different societies animated with a different spirit; some given to industry and frugality, others to dissipation and luxury. This creates separate interests among nations, and every one must be supposed under the government of a statesman, who is wholly taken up in advancing the good of those he governs, though at the expence of other societies which lie round him. This presents a new idea, and gives birth to new principles. The general society of mankind treated of in the first book, is here in a manner divided into two. The industrious providers are supposed to live in one country, the luxurious consumers in another. The principles of the first book remain here in full vigour. Luxury still tends as much as ever to the advancement of industry; the statesman’s business is only to remove the seat of it from his own country. When that can be accomplished without detriment to industry at home, he has an opportunity of joining all the advantages of antient simplicity, to the wealth and power which attend upon the luxury of modern states. He may preserve his people in sobriety, and moderation as to every expence, as to every consumption, and make them enjoy, at the same time, riches and superiority over all their neighbours. Such would be the state of trading nations, were they only employed in supplying the wants or extravagant consumption of strangers; and did they not insensibly adopt the very manners with which they strive to inspire others. As often, therefore, as we suppose a people applying themselves to the advancement of foreign trade, we must simplify our ideas, by dismissing all political combinations of other circumstances; that is to say, we must suppose the spirit universal, and then point out the principles which influence the success of it.