As the collecting such numbers of inhabitants together is a late revolution in the political oeconomy of Europe, I endeavour to give a short historical representation of it, and examine the consequences which result from it, both to the state from the growth of cities, and to the land proprietors from the desertion, as I may call it, of so many vassals and dependents. One principal effect I observe to be, the additional occupation it has given to statesmen; that is to say, political oeconomy is thereby become more complex. [Sidenote: CHAP. XI.] Formerly the inhabitants were dispersed, and by sucking, as it were, their mother earth, were more easily subsisted: now industry has gathered them together, and industry must support them. The failing of industry, is like the cutting off the subsistence of an army. This is the care of a general to prevent, that the care of a statesman. The supporting industry means no more than employing those who must live by it; and keeping their numbers in proportion to their work. The first point, therefore, is to find work for the present inhabitants; the second is, to make them multiply, if the demand for their labour increases. Increasing numbers will never remove, but rather augment such inconveniencies, as proceed from the abuses of those already existing. In order to employ a people rightly, it is proper to know the exact state of numbers necessary for supplying the demand for every occupation; to distribute those who must live by their industry into proper classes; and to make every class (as far as possible) at least, support their own numbers by propagation. [Sidenote: CHAP. XII.] Where the value of any species of industry is not sufficient for that purpose, a proper remedy must be applied. When any are found incapable, from age or infirmities, to gain their livelihood, they must be maintained. Infants exposed by their parents must be taken care of, and thrown back into the lowest classes of the people; the most numerous always, and the most difficult to be supported by their own propagation. Marriage, without assistance, will not succeed in a class who gain no more by their industry than a personal physical necessary. Here our oeconomy differs widely from that of the antients. Among them marriage was encouraged in many ways; but it was only for the free. These did not amount to one half of the people. The slaves who represented our lower classes were recruited from other countries, as they are at present in America.