148 BINNEY'S CASE—2 BLAND.

on which a ship may safely float; but it is uniformly the port at
which, owing to a variety of concurring circumstances, artificial

*and natural, she must stop; because the object of her voy-
158 age must there end.

There is a material difference between legislative enactments
relative to the formation of an improved river navigation, and
those in relation to proper navigable canals; because of the mate-
rial difference between the two subjects. The forms and modes of
the two kinds of navigation are essentially different; and there-
fore, inferences and principles, fairly deducible from, or applica-
ble to one, cannot, with any propriety, be made from, or to the
other.

The River Thames, in England, is navigable above London, for
a considerable distance; and the vessels, which pass up it, are all
provided with a self-moving power; many of them have a horse on
board, to be sent out for towing, when it can be done. Sails are
used, where an opportunity offers, and where not, they use oars,
or setting-poles. For some spaces they have the privilege of a
towing-path on the bank, from which the horse is made to tow the
boat; and in other spaces the horse is driven into the river, to
wade along, and draw the boat after him. On the River Severn,
in England, a towing-path, from which vessels are drawn along
up or down the river, is claimed by custom, and has been con-
firmed by statute. Hale de Port Maris, 86; 23 Hen. 8, c. 12. In
some spaces of river navigation, the vessel is lifted up, or let down
into short canals, and thus passed by innavigable rapids; in others,
its safe passage is secured by means of dams, sluices, or cuts. The
whole course of river navigation is irregular in its modes of move-
ment; but the vessel proceeds throughout by having with it, from
the very port, whence it sets forth, a moving power suited to each
mode of navigation, either of which may be used according as it
may be most beneficial; and that too, through a wide, deep, and
occasionally a rapidly descending stream. The Act incorporating
the Potomac Company furnishes a complete example of river navi-
gation. By that Act the rapid, headlong River Potomac, above
tide, was to be made navigable; its i'alls were to be surmounted by
locks and canals; its ripples were to be opened by cuts; and its
shallows were to be cleared so that boats might pass up or down
with safety.

Proper canal navigation is uniform in its movements and limited
to one kind oi' propelling power; that is, by means of a towing
path; and it is rarely, or ever permitted to use any other. The

* vessel itself is built and laden just so as to float upon still
low water, unagitated, and without a ripple or wave. All which
gives to this form of transportation a peculiarity of character,
which renders it necessary that the canal, for which it is alone
and exclusively adapted, should terminate at that point where it