Then come rivers, swamps, accidents, heavy and muddy roads; these are so many _difficulties_ to be overcome; in order to do which, causeways are constructed, bridges built, roads cut and paved, railroads established, etc.

But all this is costly, and the article transported must bear its portion of the expense.

There are robbers, too, on the roads, and this necessitates guards, a police, etc.
Now, among these _obstacles_, there is one which we ourselves have placed, and that at no little expense, between Brussels and Paris.

This consists of men planted along the frontier, armed to the teeth, whose business it is to place _difficulties_ in the way of the transportation of goods from one country to another.

These men are called custom-house officers, and their effect is precisely similar to that of steep and boggy roads.