therefore cannot be expected that any individual or small number of individuals should erect or maintain. The performance of this duty requires, too, very different degrees of expense in the different periods of society.

After the public institutions and public works necessary for the defence of the society, and for the administration of justice, both of which have already been mentioned, the other works and institutions of this kind are chiefly those for facilitating the commerce of the society, and those for promoting the instruction of the people.

The institutions for instruction are of two kinds: those for the education of youth, and those for the instruction of people of all ages. The consideration of the manner in which the expense of those different sorts of public, works and