As there are two cases in which it will generally be advantageous to lay some burden upon foreign for the encouragement ofdomestic industry, so there are two others in which it may sometimes be a matter of deliberation, in the one, how far it is proper to continue the free importation of certain foreign goods; and, in the other, how far, or in what manner, it may be proper to restore that free importation, after it has been for some time interrupted.