The measure of this last species of _necessary_, is determined only by general opinion, and therefore can never be ascertained justly; and as this opinion may have for its object even those who are below the level of the _physical-necessary_; it often happens, that we find great difficulties in determining its exact limits. It may appear absurd, to suppose that any one can enjoy _superfluity_ (which we have called the characteristic of _political-necessary_) to whom any part of the _physical-necessary_ is found wanting. However absurd this may appear, nothing, however, is more common among men, and the reason arises from what has been observed above. The desires which proceed from the affections of his mind, are often so strong, as to make him comply with them at the expence of becoming incapable of satisfying that which his animal oeconomy necessarily demands. From this it happens, that however easy it may be to conceive an accurate idea of a physical-necessary for _animals_, nothing is more difficult, than to prescribe the proper limits for it with regard to _man_. This being the case, let us suppose the condition of those who enjoy but little superfluity, and who fill the lower classes of the people, to be distinguished into three denominations; to wit, the highest, middle, and lowest degree of physical-necessary; and then let us ask, how we may come to form an estimation as to the respective value of the consumption implied in each, in order to determine the minimum as to the profits upon industry. This question is of great importance; because we have shewn that the prosperity of foreign trade depends on the cheapness of manufacturing; and this again depends on the price _of living_, that is of the physical-necessary for manufacturers. One very good method of estimating the value of the total consumption implied by this necessary quantity, is to compute the expence of those who live in communities, such as in hospitals, workhouses, armies, convents, according to the different degrees of ease, severally enjoyed by those who compose them. In running over the few articles of expence in such establishments, it will be easy to discern between those, which relate to the supply of the physical, and those which relate to the supply of the political-necessary: ammunition bread is an example of the first; a Monk’s hood and long sleeves, are a species of the latter. When once the real value of a man’s subsistence is found, the statesman may the better judge of the degree of ease, necessary or expedient for him to allow to the several classes of the laborious and ingenious inhabitants. As we have divided this physical-necessary into three degrees; the _highest_, _middle_, and _lowest_; the next question is, which of the three degrees is the most expedient to be established, as the standard value of the industry of the very lowest class of a people.