present carry on a very considerable commerce with each other, and by mutually affording a market, give a good deal of encouragement to each other’s industry.

Since such, therefore, are the advantages of water-carriage, it is natural that the first improvements of art and industry should be made where this conveniency opens the whole world for a market to the produce of every sort of labour, and that they should always be much later in extending themselves into the inland parts of the country. The inland parts of the country can for a long time have no other market for the greater part of their goods, but the country which lies round about them, and separates them from the sea-coast, and the great navigable rivers.

The extent of their market, therefore, must for a long time be in