He has calculated that the day on which he returns the plane, accompanied by the remuneration agreed upon, he will have effected more work, with the same labor, thanks to this tool.

A profit will remain to him, otherwise he would not have borrowed.

The two services of which we are speaking are exchanged according to the law which governs all exchanges, the law of supply and demand.

The claims of James have a natural and impassable limit.

This is the point in which the remuneration demanded by him would absorb all the advantage which William might find in making use of a plane.