The obstruction of the circulation of labour and capital from employment to employment, and from place to place. In the last-mentioned instances of protection, none of these evils take place. ------- The general principles of Exchange are so few and obvious that there would be little need to enlarge upon them but for their perpetual violation. To leave all men free to seek the gratification of their wants seems a simple rule enough; and universal experience has shown, not only that wants freely expressed are sure to be supplied, generally to the advantage of both parties, but that every interference of authority, whether to check or stimulate the want,— to encourage or discourage the supply, proves an aggression on the rights of industry, and an eventual injury to all concerned. All that governments have to do with the exchanges of nations, as of individuals, is to protect their natural freedom; and, if a system of indirect taxation be the one adopted, to select those commodities for duty which are not necessary enough to subject the lowest class to this species of tax, while they are desirable enough to induce others to pay the additional cost. It may be a question whether this method of raising revenue be wise: there can be no question that a government directly violates its duty when it grants privileges (real or supposed) to one class above another. But, it is said, governments have always shown more or less of this partiality. May it be confidently anticipated that they will ever cease to transgress the legitimate bounds of their power?