t lands was put in issue,
the contention was advanced that "disposal is not letting or leasing,"
and that Congress has no power "to give or authorize leases." The Court
sustained the leases, saying "the disposal must be left to the
discretion of Congress."[253] Nearly a century later this power to
dispose of public property was relied upon to uphold the generation and
sale of electricity by the Tennessee Valley Authority. The reasoning of
the Court ran thus: the potential electrical energy made available by
the construction of a dam in the exercise of its constitutional powers
is property which the United States is entitled to reduce to possession;
to that end it may install the equipment necessary to generate such
energy. In order to widen the market and make a more advantageous
disposition of the product, it may construct transmission lines, and may
enter into a contract with a private company for the interchange of
electric energy.[254]

PUBLIC LANDS

No appropriation of public lands may be made for any purpose except by
authority of Congress.[255] However, the long-continued practice of
withdrawing land from the public domain by Executive Orders for the
purpose of creating Indian reservations has raised an implied delegation
of authority from Congress to take such action.[256] The comprehensive
authority of Congress over public lands includes the power to prescribe
the times, conditions and mode of transfer thereof, and to designate the
persons to whom the transfer shall be made;[257] to declare the dignity
and effect of titles emanating from the United States;[258] to determine
the validity of grants which antedate the government's acquisition of
the property;[259] to exempt lands acquired under the homestead laws
from previously contracted debts;[260] to withdraw land from settlement
and to prohibit grazing thereon;[261] to prevent unlawful occupation of
public property and to declare what are nuisances, as affecting such
property, and provide for their abatement;[262] and to prohibit the
introduction of liquor on lands purchased and used for an Indian
colony.[263] Congress may limit the disposition of the public domain to
a manner consistent with its views of public policy. A restriction
inserted in a grant of public lands to a municipality which prohibited
the grantee from selling or leasing to a private corporation the right
to sell or sublet water or electric energy supplied by the facilities
constructed o