IMPROVEMENTS IN CANAL NAVIGATION
Year: 1850

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ARCHIBALD
SLATE, of Woodside Iron Works, near Dudley, in the County of Worcester,
Civil Engineer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Second day of November, in the fourteenth year of Her reign,
and in the year One thousand eight hundred and fifty, did, for Herself, Her
heirs and successors, give and grant unto the said Archibald Slate Her
special license, full power, sole privilege and authority, that I, the said
Archibald Slate, my exors, adññors, and assigns, or such others as I, the said
Archibald Slate, my exors, adñiors, or assigns, should at any time agree. with,
and no others, from time to time and at all times during the term of years
therein mentioned, should and lawfully might make, use, exercise, and vend,
within England, Wales, and Town of Berwick-upon-Tweed, my Invention
of "IMPROVEMENTS IN CANAL NAVIGATION;" in which said Letters Patent is
contained a proviso, obliging me, the said Archibald Slate, by an instru-
ment in writing under my hand and seal, particularly to describe and ascer-
tain the nature of my said Invention, and in what manner the same is to
be performed, and to cause the same to be enrolled in Her Majesty's High
Court of Chancery within six months next and immediately after the date of
the said in part recited Letters Patent, as in and by the same, reference being
thereto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Archibald Slate, do hereby declare the nature of my said Invention, and in
what manner the same is to be performed, and to be particularly described
and ascertained in and by the following statement, reference being had to the

page_text: Drawings hereto annexed, and to the letters and figures marked thereon, that
is to say:
My Invention of Improvements in Canal Navigation relates, in the first place,
to a method of passing boats or barges by means of a vertical equilibrium lift
from a lower level of a canal to a higher level, and visa versa; and, in the
second place, in a method of propelling boats or barges.
Over
The difference of the levels of the two arms of a canal to which the vertical
equilibrium lift may be applied is limited only by the strength of materials and
convenience of working, and for the purpose of its most extensive application
the upper level of the canal should be divided into two branches or arms, each
of a sufficient width, and carried along each side of the lower level of the canal
to a sufficient length to receive an ordinary canal boat or barge, and the
caissons or tanks hereafter, mentioned. The, sides of the canal forming the
upper and lower levels may be constructed of stone and brick work, as in locks,
or of iron, if preferred. The arrangement I should prefer as most convenient
for placing the necessary machinery would be to divide the lower level of the
canal as well as the upper level into two arms or branches, placing them about
double the width of each branch apart, and to build up the intervening space
to the same height as the sides or banks of the two branches or arms of the
upper level of the canal, as shewn in section in Figure 3 of the Drawings
annexed. The depth of each branch of the canal must be of sufficient depth
to permit a boat with an ordinary load to float over the ends of a caisson or
tank of sufficient size to contain water enough to float a loaded boat.
the arms or branches of the two levels of the canal so arranged I erect.a
wooden or iron framework in the position shewn in Figures 1, 2, and 3; upon
the top of this framework, at points immediately over the upper and lower
branches of the canal, are placed rails (as in Figure 3, a, a, a, a), as in an
ordinary railroad, upon the rails I place carriages containing a series of wheels
(b, b), over which chains. (c, c,) for lifting the caissons are to run. At the
bottom of one of the branches of the canal on the upper level, and of one of the
branches on the lower level, are placed iron caissons or tanks (d, d,) of a
sufficient size to contain water enough to float boats containing an ordinary
load, as shewn in Figures 1 and 3; these, caissons or tanks are carried by straps
attached to cross bearers (e, e, Figure 3), which are suspended by chains at
points immediately under the framework. In the centre of the framework,
in two vertical grooves, as shewn in the Drawings, Figures 1, 2, and 3, is
suspended the shaft (f), on which are four drums (g, 9, 9, 9), on which the
suspending chains wind and unwind in the operation of raising and lowering
the caissons or tanks; on each end of this shaft f (the use of, which in motion

page_text: will be hereafter described) is a bearing or journal which is grasped by an eye
or strap (h) in which it can revolve; to this strap or eye one end of the
equilibrium connecting chains (i, i, i, i,) are attached, the other end of the
equilibrium connecting chains are attached to the cams j, j, j, j, placed relatively
to the framework (as shewn in Figure 3), these cams are keyed fast on the
shaft (k), shewn in Figures 2 and 3; on the same shaft are keyed two other
cams (1, 1), to which are attached the two other equilibrium connecting chains,
as also shewn in Figures 2 and 3, and to these chains the balance' weights
(m, m,) are attached, as also shewn in Figures 2 and 3; on the same shaft are
keyed a large wheel (n) and two drums, Figure 2, (0, 0),, to these drums on
opposite sides are attached two water barrels (p,p,) to aid, if necessary, the
imanual power in working the lift. The series of wheels (7), shewn in Figure 2,
shews how the manual power may be applied. The balance weight should be
nearly equal to the caissons in the water when working through the shortest
leverage of the cams, the caissons being allowed a little weight in excess in
order that they may freely sink to the bottom. The balance weight when
acting through the longest leverage (as shewn by the dotted lines) should be
equal to balance the caissons when out of the water. The particular form of
the cams between these two points will be regulated by the form and depth of
the caissons.
The first operation of
Having described the Drawings, I will proceed to describe the equilibrium
lift in action. I will suppose two loaded boats approaching the lift, one on
the upper and the other on the lower level, but the following description will
apply as well to one boat as to two, or to empty as well as loaded boats.
Each boat is floated into the arm of the canal over the caissons or tanks lying
at the bottom, in the same way as into'ordinary locks.
lifting is to raise both caissons out of the water with the boats floating in them,
as shewn in the dotted faint lines in Figures 1 and 3; this is done by applying
power to the series of wheels (9), shewn in Figure 2, which turn the shaft (k),
by which operation the chains (i, i,) are wound on the cams, causing the
shaft (f) with the drums with suspending chains to move down the vertical
grooves to the position shewn by the dotted lines (r) in Figure 3, and thus
raising the caissons and boats out of the water. This operation may be
performed either by manual power or by the water barrels, or by the two
conjointly. The varying weight of the caissons progress of being raised
from the bottom to the surface and out of the water is arranged so as to
preserve the equilibrium throughout the operation by the varying leverage of
the, balance weight acting upon and through the four cams. Having by this
means lifted both caissons out of the water, that which is required to descend

page_text: to the lower level is moved across the bank of the canal by means of the
railway (a, a,) Figure (3), on the top of the framework, until it is suspended
over the lower branch of the canal ready to descend, as shewn by the dotted
lines, Figure 3; when in this position the wheel on the end of the shaft (f)
carrying the drums with suspending chains is geared to the series of motion
wheels by means of an ordinary shifting catch or clutch, the power is then
applied, and the shaft caused to revolve, which by unwinding the chains
attached to the descending caisson, and winding the chains attached to the
ascending caisson, carries them to a relative position opposite to that from
which they started, and they are stopped at the proper point by the top of the
cross bearer coming in contact with the bottom of the moveable chain carriage.
The caisson which has been raised from the lower level is then moved as before
by means of the railway over the side of the canal, and suspended above the
upper branch; the catch or clutch is then ungeared, the power again applied
to the shaft carrying the cams with the balance weight, and the caissons are
simultaneously lowered to the bottom of the canal, and the boats floated over
their ends and away to their destination.
I am aware that various plans for passing boats from one level of a canal to
another by vertical lifts have been proposed, and some partially carried out in
practice; in most of these, however, there is a loss or consumption of water
from the upper ponds of the canal in excess of that consumed or in diminution
of that supplied in passing the upward or downward trade respectively. It
will be obvious that the plan above proposed occasions no waste of water;
that in passing the upward trade the water consumed is equal to the tonnage
of the ascending trade, and that in passing the descending trade the water
supplied to the upper ponds of the canal is equal to the tonnage of the
descending trade, so that a weight of water equal to the whole downward
tonnage will be absolutely transferred from the lower to the higher levels of the
canal.
And I hereby declare, that I claim as my Invention the so constructing
and arranging apparatus for canal navigation that caissons may be raised and
lowered and employed for transferring boats from one to another level of the
canal, as above described.
My method of propelling boats or barges consists in using compressed air
for the purposes of propulsion, such air being compressed either in the boat to
be propelled, or in any one of a series of boats connected together, and conveyed
from that boat to the others by means of a flexible air-tight pipe, the air so
compressed and conveyed being allowed to escape through or from a muzzle
at the bottom and stern of the boat or barge; the muzzle being of such an

page_text: area that the air may issue at a velocity very slightly greater than the boat is
required to travel at, and that the pressure of the compressed air multiplied
into the area of the muzzle may equal the tractive power applied by a horse in
drawing a boat at the same velocity; for example, suppose the tractive power
applied by a horse to be one hundred and thirty-five pounds at two and a half
miles per hour, and the boat to be three feet deep in the water above the
muzzle, there would be a pressure upon the muzzle of one and a half pounds
per square inch, and 135 + 1 = 90 inches area of muzzle; and if the air
were expelled or allowed to escape from this muzzle, against which there is a
pressure of one and a half pounds per inch, at a velocity slightly greater than
the two and a half miles per hour to be allowed for what is technically called
the slip of all propellers applied to water, then it follows that the boat will be
propelled forward with the same velocity as a horse would draw it.
I am aware that it has been proposed to employ compressed air for the
purpose of propelling vessels, but what I claim is the constructing and adapting
apparatus for canal navigation, in such manner as that the compressed air
supplied as aforesaid may be allowed to escape from muzzles in each separate
boat at a velocity slightly greater than that at which the boat is required to
travel.
In witness whereof, I have hereunto set my hand and seal, this Twenty-
eighth day of April, One thousand eight hundred and fifty-one.
the year of our Lord 1851, the aforesaid Archibald Slate came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that purpose.
Enrolled the Twenty-ninth day of April, in the year of our Lord One