vernment."[354] The Court answered:
"In this case it is admitted that the steamer was engaged in shipping
and transporting down Grand River, goods destined and marked for other
States than Michigan, and in receiving and transporting up the river
goods brought within the State from without its limits; * * * So far as
she was employed in transporting goods destined for other States, or
goods brought from without the limits of Michigan and destined to places
within that State, she was engaged in commerce between the States, and
however limited that commerce may have been, she was, so far as it went,
subject to the legislation of Congress. She was employed as an
instrument of that commerce; for whenever a commodity has begun to move
as an article of trade from one State to another, commerce in that
commodity between the States has commenced."[355] Turning then to
counsel's _reductio ad absurdum_, the Court added: "We answer that the
present case relates to transportation on the navigable waters of the
United States, and we are not called upon to express an opinion upon the
power of Congress over interstate commerce when carried on by land
transportation. And we answer further, that we are unable to draw any
clear and distinct line between the authority of Congress to regulate an
agency employed in commerce between the States, when the agency extends
through two or more States, and when it is confined in its action
entirely within the limits of a single State. If its authority does not
extend to an agency in such commerce, when that agency is confined
within the limits of a State, its entire authority over interstate
commerce may be defeated. Several agencies combining, each taking up the
commodity transported at the boundary line at one end of a State, and
leaving it at the boundary line at the other end, the Federal
jurisdiction would be entirely ousted, and the constitutional provision
would become a dead letter."[356] In short, it was admitted
inferentially, that the principle of the decision would apply to land
transportation; but the actual demonstration of the fact still awaited
some years.[357] See _infra_.

HYDROELECTRIC POWER

As a consequence, in part, of its power to forbid or remove obstructions
to navigation in the navigable waters of the United States, Congress has
acquired the right to develop hydroelectric power, and the ancillary
right to sell it to all takers. By a long-standing doctrine of
Constitutio