IMPROVEMENT APPLICABLE TO INLAND NAVIGATION
Year: 1834

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JoHN
TWISDEN, of Halberton, near Tiverton, in the County of Devon, a Commander
in the Royal Navy, send greeting.
WHEREAS His most Excellent Majesty King William the Fourth, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twenty-fourth day of July, in the fifth year of His reign, did,
for Iimself, His heirs and successors, give and grant unto me, the said John
Twisden, His especial licence that I, the said John Twisden, my exors, adiñiors,
and assigns, or such others, as I, the said John Twisden, my exors, admors,
and assigns, should at any time agree with, and no others, from time to time
and at all times during the term of years therein expressed, should and
lawfully might make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, my Invention of "IMPROVEMENT APPLICABLE
TO INLAND NAVIGATION;" in which said Letters Patent there is contained a
proviso obliging me, the said John Twisden, by an instrument in writing
under my hand and seal, particularly to describe and ascertain the nature of
my said Invention, and in what manner the same the same is to be performed,
and to cause the same to be inrolled in His Majesty's High Court of Chancery
within six calendar months next and immediately after the date of the said
recited Letters Patent, as in and by the same, reference being thereunto had,
will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Twisden, do hereby declare that the nature of my said invented improve-
ments, and the manner in which the same is to be performed, is described
and ascertained as follows, that is to say:-

page_text: They consist in additions and improvements on Doctor Anderson's perpen-
dicular lift for raising and lowering boats and vessels from one level to
another of a canal, for the purpose of saving water, and in situations where
it is inconvenient or impractable to have an under drain to keep the lower
chamber free from water, for the reception of the lower coffer. These additions
and improvements are coloured red in the accompanying sketch, only claiming
the addition of the chambers for reception of the boats on leaving and entering
the coffers in the first case, and to the increased capacity of the coffer in the
other case, without claiming a right to the lift, or to any of the machinery,
sluices, or gates used in working the same.
Let there be a sufficient pipe or conduit D from the upper level on the right
side of the lift to the lower level on the left, and a similar pipe or drain
from the upper level on the left side to the lower level on the right.
Let there be a stop, rest, or stay at the height the coffer C will be per-
mitted to rise by the lower water, stopping the descent of the opposite
coffer at a few inches below that depth, say, three feet below the bottom.
of the upper level of the canal; make a chamber or small lock B, to
admit the boat A to and from the coffer. Let the communication with the
upper level be guarded by a gate or sluice, and the communication with the
coffer by a similar guard or device. Let the lower camber B be guarded by
a gate or sluice, so as to retain the water at three fect, or a suitable height
above the top level of the lower canal, and at a sufficient distance from the
end of the lower coffer to get the boat therein. To get a boat from the lower
to the bigher level of the canal, let the boat A be drawn into the chamber B,
and the upper coffer C be secured from descending by a stop or trigger or
other device; the gate being shut, and water admitted by the conduit or
pipe D, the boat will rise as in a lock, till, being on a level with the coffer
C it may be admitted, and the gate shut, when the water may be discharged
from the chamber B into the lower level of the canal. The action of the
machine being then ready, the man below rings a bell, the man above having
been till this time preparing to get a boat from the higher to the lower level
of the canal. The boat A on the upper level of the canal must be drawn
into the chamber B, the gate being shut to cut off the communication with
the upper canal. The water in the chamber B must be let down through the
pipe D to the lower chamber B, when the boat A, descending as in a lock
to the level of the coffer C, the gates may be opened, and the boat passes
into the coffer, and having shut the gate of the chamber, and the gate of the
coffer, the stop may be removed, and the coffer with the boat be allowed to
descend. The same effect may be produced by letting coffer C, Figure 2, be
made water-tight to twice the depth of the lower canal, with gates to the

page_text: same at each end, one pair to retain the water to about the depth of the
canal, another pair above the same height, each pair opening independant of
the other, the lower gates falling on the bottom of the coffer, the upper
gates so hung as to draw to the top of the coffer, the boats being intended
to pass between these gates. The action of the machine will then bc, to
get a boat from the lower level to the upper level of the canal, let the lower
coffer C be filled with water, so as to descend to the bottom of the canal,
when the upper coffer must be stopped and retained by a trigger or firm
support. Then the water must be let out of the lower coffer to the level of the
lower canal, when the boat A may be drawn into the coffer; the gate must
be shut, and being then prepared, the man below rings a bell; the man above
having put a boat into the upper coffer, or having filled it with water to the
height of the lower gates of the coffer, and being prepared with a friction
wheel or band, to prevent the too rapid descent for the first two or three
feet, may proceed to lower the coffer, when the operation may be continued,
alternately changing, as it may be found necessary. It may be observed, that
letting out water from the ascending coffer, at times when the lower level of the
canal may be a few inches higher than usual, will facilitate the operation.
N.B. The first plan of having chambers in the manner of small locks at
the head and foot of the lifts is the safest and best. The latter of doubling
the capacity of and depth of the coffers, though applicable in some cases,
seems less desirable on account of the great care requisite in lowering them
through the first three fect of their descent.
In witness whereof, 1, the said John Twisden, have hereunto set my hand
and seal, this Seventeenth day of September, in the year of our Lord
One thousand night hundred and thirts Coun