David Josiah Brewer,
Monongahela Navigation Company v…
“ Congress has the same power to regulate commerce upon the land as upon the water. A river, to be sure, is a natural channel; but, if it is not a navigable one, it can no more be used for the purposes of commerce than the land, and therefore to convert it from the mere natural channel into a public highway, for commercial purposes, and to levy a toll to reimburse the expense, no more conflicts with the powers of congress over the commerce of the country than the construction of a canal or a turnpike for the same purposes, with the same tolls. ”
