The strict constructionists were destined to spend many unpleasant hours over this question of inland commerce. That the Union had control of ocean or foreign commerce, no one denied. The ocean is common to all. But fresh water lies inland, among the States. Strict construction would not allow the central authority to undertake a public work in an individual State. Clearing waterways and constructing harbours might have been left to the respective States, if each stream and each lake had been located entirely within the confines of some State. Interstate commerce thus began early to play a part in making the Union. In former days, Congress had granted requests of Rhode Island, Maryland, and Georgia to be allowed to retain part of their imposts for completing their public works on rivers and harbours. The privilege was extended to other State at various times, the expenditures being withheld from the national revenues. The system was bad and produced frequent delay and abuse. It was really the Federal Government making the improvements indirectly. Evidently the work could be carried on more uniformly and systematically under central management. Precedent had been established under the compulsion of war. The Carondelet canal was a private enterprise connecting Lake Pontchartrain with the city of New Orleans. Congress appropriated a sum of money, as the war came on, for making the canal navigable for the gunboats in order to protect New Orleans. Several similar instances might be cited during the progress of the war. Under such conditions, it was an easy matter to include in the Army Appropriation bill of 1819 a sum for making a complete survey of all watercourses tributary to the Mississippi on its western side, and on its eastern side north of the Ohio. There was in the same bill an appropriation for making surveys with maps and charts of the Ohio and Mississippi rivers, from the Falls of the Ohio to New Orleans, "for facilitating and ascertaining the most practical mode of improving the navigation of those rivers." No promise was made, but the ultimate purpose was to have the individual States or the Union improve the navigation of all these waterways. So insidiously was necessity making the Republicans commit themselves to the policies of their predecessors, that no one realised they were preparing by these actions to inaugurate the vast work of public improvement in the interior of the continent which characterised the middle period of American history.