late as the sixteenth century, but the method of regulating the waters
of a river by weirs is immemorial.

We have no earlier record of weirs upon the Thames than that in Magna
Charta; but some such system must have existed from the time when men
first used the Thames in a regular manner for commerce.

There is but one place left in which one can still reconstruct for
oneself the aspect of such weirs as were till but little more than a
century ago the universal method of canalising the river. Modern weirs
are merely adjuncts to locks, and are usually found upon a branch of
the stream other than that which leads up to the lock. But in this
weir the old fashion of crossing the whole stream is still preserved.
There is no lock, and when a boat would pass up or down the paddles of
the weir have to be lifted. It is, in a modern journey upon the upper
Thames, the one faint incident which the day affords, for if one is
going down the stream but few paddles are lifted, and the boat shoots
a small rapid, while to admit a boat going up stream the whole weir is
raised, and, even so, a great rush of water opposes the boat as it is
hauled through. Some years ago there were several of these weirs upon
the upper river. They have all been superseded by locks, and it is
probable that this last one will not long survive.

Such weirs did certainly sufficiently regulate the stream as to make
its banks regularly habitable. If no local order, at least the
interest of villagers in their mills sufficed to the watching of the
stream.

We have in the place names upon the Thames a further evidence of the
antiquity of its regulation, for, as will be seen in a moment, none