Food is not the only need of man. Shelter and clothing, without being as rigorously indispensable (especially in warm countries), are nevertheless of great utility to maintain a certain equilibrium between the temperature of our bodies and the external temperature; for it is well known that the derangement of this equilibrium is one of the most ordinary causes of illness. Nature not having clothed man as she has the other animals, he is obliged to provide himself with clothes by his industry. As for habitations, several animals know as well as man how to construct them: for example, beavers and rabbits; and despite the indisputable superiority of his art, this is yet, as we see for man, but the development of an instinct which he shares with other creatures. These various wants, then, which to be satisfied demand a certain number of material objects, such as food, houses, clothing, etc., carry with them others in their train: for example, the need of locomotion to procure what is wanted: hence, carriages, boats, etc.;--the need of protecting one's self against those who would take from us what we possess: hence, arms of every kind;--the need of repose and order in the house: hence, furniture of every sort;--in a higher degree again the need of pleasing the imagination: hence, works of art, pictures, statuary;--the need of information: hence, books, etc. Finally, and independently of all these different things, there are yet two which deserve to be specially noticed, because of their particular and distinctive character. These are, first, land, which is the common and inexhaustible source of all riches, the only thing that does not perish, and which is always found again in the same quantity after as well as before the enjoyment of it; land, which is as the substance, the very basis of riches;[98] and the second, money (gold or silver, with their representative, paper), which is of a nature to be exchanged against all kind of merchandise, even land, and which, consequently, represents them all. These two kinds of things, land and money, the one an essential, the other a condensed image, of all wealth, are the two most natural objects of man's desires, because, with the one or the other, he can procure all the rest. We have not to examine here how man succeeds in securing to himself the exclusive enjoyment of these several goods: we shall treat the subject of property further on, and shall explain in what, and why, it is inviolable. Let it suffice to say here that these goods being bound up with the very preservation of our existence, the desire and instinct which lead us to appropriate them, have nothing blameworthy in themselves. External goods being necessary to life, we have to consider how we should use them when we possess them, and how acquire them when we do not possess them.