n Waring _v._
Clarke,[365] when the Court ruled that the admiralty jurisdiction under
the Constitution was not to be limited or interpreted by English rules
of admiralty and extended the jurisdiction of the federal courts to a
collision on the Mississippi River ninety-five miles above New Orleans.
In this ruling the Court moved in the direction of accommodating the
rising commerce on the inland waterways and prepared the way for the
Genesee Chief,[366] which reversed The Thomas Jefferson and sustained
the constitutionality of an act of Congress passed in 1845 giving the
district courts jurisdiction over the Great Lakes and connecting waters,
and so in effect extended the admiralty jurisdiction to all the
navigable waters of the United States.[367] The Genesee Chief therefore
vastly expanded federal power,[368] and marked a trend which was
continued in Ex parte Boyer,[369] where admiralty jurisdiction was
extended to canals, and in The Daniel Ball,[370] where it was extended
to waters wholly within a given State provided they form a connecting
link in interstate commerce. This latter case is also significant for
its definition of navigable waters of the United States as those that
are navigable in fact, and as navigable in fact when so "used, or * * *
susceptible of being used, in their ordinary condition, as highways for
commerce, over which trade and travel are or may be conducted in the
customary modes of trade and travel on water."[371] The doubts left by
the Ball case in its distinction between navigable waters of the United
States and navigable waters of the States were clarified by In re
Garnett,[372] where it was held that the power of Congress to amend the
maritime law was coextensive with that law and not confined "to the
boundaries or class of subjects which limit and characterize the power
to regulate commerce," and that the admiralty jurisdiction extends "to
all public navigable lakes and rivers." In United States _v._
Appalachian Electric Power Co.,[373] the concept of "navigable waters of
the United States" was further expanded to include waterways which by
reasonable improvement can be made navigable for use in interstate
commerce provided there is a balance between cost and need at a time
when the improvement would be useful. Nor is it necessary that the
improvement shall have been undertaken or authorized. Conversely, a
navigable waterway of the United States does not cease to be so because
navigation ha