769 [=130] (V.2)

767

piling or walls, the intermediate
space being filled with heavy
material, on the same plan as
has been described elsewhere. The
flanks of these bridges are also
covered buy either piling or retain-
-ing walls, and throughout the
whole of the series there has been
no deviation from the standard
plan as originally laid down.
The gates and apparatus for
opening and shutting are pre-
-cisely the same as those which
have been figured in Diagram LXXIII
Fig. 1 of the last chapter. They
consist of a drop gate 6 feet in
depth which is held in suspension
by bar chains fixed to windlasses.
On closing the canal these gates
are relieved from their suspended
position, by raising the ratchet
catches with the end of a marlin
spike, the attached chains being
afterwards removed by [an arrange-, struck through]
[-ment which admits of, struck through] the hooks
being detached from the gates by
a lateral movement; sleepers are
dropped [left bracket symbol in text] one above another on the
top of the gate until the bay
is suffuciently closed; [I have, struck through]
[before said that, struck through] To close and
open one of these bays with the
apparatus above described, the
time occupied is about 33 minutes
and considering that in the case
of the branch heads time is of
less importance than it is at
the dam regulators, and that
leakage is, to a certain extent,
of no consideration at all, the
[means in, struck through] establishment that
is provided for the working of
the machinery will do ample
justice