Secondly: Patent-right cannot be justified on the lower ground of expediency. The object of a Patent-Law, in the supposed interest of the community, is to stimulate invention. But invention needs no artificial stimulus. Nature has amply provided all needful and wholesome encouragement, in the additional profit afforded by improved methods of production. In the natural course of business, every producer is spurred on by his material interests to invent for himself or to encourage the inventions of others. The whole history of industrial progress is an unceasing striving after improvement, with a view to profit. The few thousand patented inventions are as nothing compared with the innumerable improvements produced daily and hourly in the ordinary course of business, with the vulgar view of gain. The best stimulus to invention, therefore, will be found in the natural competition of producers; but Patent-Law destroys this competition by an unjust monopoly, and thus tends indirectly to weaken the natural impulse to improvement. Invention may be even over-stimulated. In all her arrangements, Nature provides for a due equilibrium of powers and tendencies. Thus the various faculties and temperaments of man—the sanguine and the cautious, the speculative and the practical—are nicely balanced. The result, when things are left to themselves, is a happy combination of ingenuity and caution, and, as a consequence, a continuous but prudent course of improvement. But if, by conventional rewards, we give a factitious impulse to the inventive faculty, we destroy the natural equilibrium of capacities, and foster a scheming, fanciful turn of mind, at the expense of thoroughness and a patient working out of sound ideas. This result has actually occurred in the United States, where the factitious value attached to invention has tended to produce an almost total sacrifice of solid workmanship to a flimsy ingenuity. Patent-Law does not even attain its proposed end of quickening the progress of real improvement; on the contrary, it is found in practice seriously to hinder it, the monopoly granted to one inventor necessarily obstructing the progress of every other. Hence, an eminent inventor has lately said: “The advance of practical science is now grievously obstructed by those very laws which were intended to encourage its progress.” That Patents seriously obstruct the natural development of ideas, is best seen by the sudden advance which usually follows the expiry of important Patent-rights. The natural course of improvement, dammed back by artificial obstruction during the continuance of the Patent, is set free on its conclusion, and a new impulse is given to the development of ideas and their practical application.