Factitious reward is superfluous, whenever natural reward is adequate to produce the desired effect.
Under this head may be classed all inventions in the arts, which are useful to individuals, and whose products may become articles of commerce. In the ordinary course of commerce, the inventor will meet with a natural reward exactly proportionate to the utility of his discovery, and which will unite within itself all the qualities which can be desired in a factitious reward. After the most mature consideration, no sovereign can find another measure so exact as is thus afforded by the free operations of trade. All that the government has to do is to secure for a time, to the inventor, whatever benefit his discovery may yield. This is generally done by the grant of an exclusive privilege or patent.