A NEW MECHANICAL POWER FOR THE PURPOSE OF LIFTING WEIGHTS, MOVING SHIPS, WEIGHING ANCHORS, &c.
Year: 1799

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HOTCHKIS, Esquire, Lieutenant in His Majesty's Navy, send greeting.
WHEREAS His most Excellent Majesty King George the Third did, by
His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Third day of October, in the thirty-ninth year of His reign,
give and grant unto me, the said John Hotchkis, His especial licence, that I,
the said John Hotchkis, during the term of years therein mentioned, should
and lawfully might use, exercise, and vend, within England, Wales, and the
Town of Berwick-upon-Tweed, and also in all His Majesty's Colonies and
Plantations abroad, my Invention of "A NEW MECHANICAL POWER FOR THE
PURPOSE OF LIFTING WEIGHTS, MOVING SHIPS, WEIGHING ANCHORS, &c.;" in which
said Letters Patent there is contained a proviso, obliging me, the said
John Hotchkis, by an instrument in writing under my hand and seal, to
cause a particular description of the nature of my said Invention, and in
what manner the same is to be performed, to be inrolled in His Majesty's
High Court of Chancery within one calendar month after the date of the
said recited Letters Patent, as in and by the same, relation being thereunto
had, may more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Hotchkis, do hereby declare that my said Invention is described in the
above Drawings and the following description thereof:-
The principle upon which this new mechanical power acts is that of a steel-
yard with two arms, one of the arms consequently longer than the other arm,

page_text: and bearing upon two or more pivots, and worked by a lever or power in
whatever way it may be applied to the steelyard. Purchase: The weight
which is to be lifted is made to bear upon both arms of the steelyard by
means of a rope or chain, which is rove through a block or pulley, so that the
weight to be lifted is made to assist in lifting itself in the proportion which the
short arm of the machine bears to the long arm. The difference of weight
which is upon the long arm of the steelyard more than what is upon its short
arm is all of the weight which bears on both of the arms, which the lever or
working power by which this machine is moved has to lift, therefore the
nearer that the two arms are of the same length the greater will the power be
encreased by this new mechanical principle; but if the two arms are made
exactly of the same length the machine becomes a balance, and is no longer a
mechanical power, because the weight suspended to the block or pulley will
gain nothing in hight in turning the machine round. But, to demonstrate
how this new mechanical principle acts more clearly, let A, B, in Figure
First, represent a line passing through the centre of a capsten or windlass which
revolves upon its pivots at A and at B, the diameter of whose larger barrel,
C, D, is three feet, and the diameter of whose smaller barrel, E, F, is 2 feet;
and let a rope G be put round the capsten at D, and this end made fast to this
larger barrel or held by men, the other end rove through the block or pulley
I, and put round the smaller barrel of the capsten at E the contrary way to
what it is upon the larger barrel of the capsten, and also made fast to it or
held by men; now it is evident that the weight which is attached to the
block or pulley I, and suspended over the roller K, bears upon the capsten at
E in the proportion which the arm E, H, on one side of the line passing
through the centre, bears to the arm D, L, on the opposite side of the line
passing through the centre; that is to say, in a capsten or windlass of these
dimensions E, I would bear a proportion of 0.4, of the weight suspended to
the block I, and D, L would bear a proportion of 0.6 of the same weight,
(viz, the weight at the block 1); and suppose the weight attached to the
block I to be 100 libs., E, HI would bear 40 of these libs., and D, L would
bear. the remaining 60 of the 100 libs.; now, the 40 libs. borne by E, H are
not only taken of the 100 libs., but when the capsten is hove upon by the
lever or working power it is made to assist in lifting the 60 libs. which bears
upon the arm D, L; but, as E, H is shorter than D, L, E H will require an
additional proportion of weight more than the difference of weight between
the two arms; that is to say, E, H would require 33% or more weight
than D, L, to balance D, L, because E, H, is 333 or shorter than D, L;
now, the 333 or of 60 libs. is 20 libs., which being added to the difference

page_text: of weight between the two arms, the sum of both weights will be 40 libs.,
which 40 libs. being attached to E, I, and what farther weight was found
necessary to overcome the friction on the machine, I say E, H would balance
D, L, consequently the 100 libs. would be weighed, or the power is encreased
2.5 times more than by the larger barrel worked by itself; and suppose the
lever that this machine is worked by is ten feet long, the power will bo
increased in the whole-
of weight between the two arms, the sum of both weights will be 40 libs.,
which 40 libs. being attached to E, H, and what farther weight was found
necessary to overcome the friction on the machine, I say E, H would balance
D, L, consequently the 100 libs. would be weighed, or the power is encreased
2.5 times more than by the larger barrel worked by itself; and suppose the
lever that this niachine is worked by is ten feet long, the power will bo
increased in the whole:-
Gained by the lever
Gained by the block the rope is rove
through
the lever power
Gained by the small barrel working against
the larger 2.5
The whole increase of power in this machine is
+
6.60 times.
+
6.60 do. or it doubles
;
13.20
2.5 X
6600
2640
33.000
or 3.03 libs. made to act upon the end of the lever, and what more was found
necessary to overcome the friction would weigh the 100 libs. suspended to the
block, and it would gain in hight in one turn round of the capsten half the
difference of the circumferences of the two barrels of the capstan, that is, 1·5 feet."
As cranes and presses are machines which this new principle can be applied to
with great effect, and as there is no occasion for the two barrels of the
machine being in one piece, as was shewn in the capsten or winlass repre-
sented in Figure 1st, and in the explanations to that Figure, and as much less
room will be taken up by having the two barrels or rollers which compose the
power by which this new mechanical principle acts separate, but parallel each
to each, and connected at one or both ends, and made to work against each
other by the means of toothed wheels, cogs, or bands, a farther description
of the principle acting upon the two barrels or rollers when separate, and
shewing that both machines act upon the same mechanical principle, is here
clemonstrated:Let A, B (see Figure Second) represent a line passing
through the centre of a roller whose diameter, C, D, is 15 feet, and which
revolves upon its pivots at A and at B; and let E, F represent a line passing
through the centre of another roller G, H, whose diameter is 1-25 feet, and
which revolves on its pivots at E and at F, the two rollers parrallel each to
each, and connected to each other by means of the toothed wheels at both of

page_text: their ends, the wheels of both rollers to be of the same diameters, and let one
end of the rope I be put round the larger roller at C and D, and this end
made fast to the roller, and let the other end of this rope I be rove through
the block K and put round the smaller roller at G and H, so as to make this
roller pull the contrary way to the larger roller when there is any weight
attached to the block K, and suspended over the wheel N; now, it is
evident that the weight attached to the block K bears upon G in the
proportion which the arm G, L, in the smaller roller, bears in length to the
arm C, M, in the larger roller (that is to say), G, L bears of the weight
attached to the block K, 0.4545 parts, and C, M bears 0.5455 parts of the
same weight; and suppose that weight to be 100 libs., the arm G, L would
bear 45 45 libs., and C, M would bear the remainder of the 104 libs., viz,
54.55 libs.; now, the weight borne by G, L is not only taken off from the
100 libs., but it is made to assist in lifting the 54.55 libs. which bears upon
C, M; but as the arm G, L is shorter than the arm C, M, by th part of the
length, therefore there must be an additional weight of th of the weight which
bears upon C, M, more than the difference of the two weightsb etween the
arms, to make G, L balance C, M (that is to say), that the difference. of
weight between the two arms, which is 9.1 libs., and th part of 54 55 libs.,
which is 9.091 libs., the sum of two weights being 18-19 libs.; this
additional weight, with what is found necessary to overcome the friction, being
attached to the arm G, L, the two arms will balance, consequently the 100
libs. will be weighed, or the power would be encreased 5.5 times; and suppose
the lever which this machine is worked by to be 10 feet in length, the power
altogether will be increased in these different proportions (viz¹):-
By the lever
13.8 times.
or 0.6836 of a lib. made to act upon the end of the lever, and what else was
found necessary to overcome the friction on the machine, the 100 libs.
attached to the block would be weighed, and would gain in heght in one turn

page_text: round of the rollers half the difference of the two circumferences of the two
rollers, or 375 of a foot. Therefore from what has been demonstrated it is
evident that a machine constructed upon the plan of Figure Second acts upon
the same mechanical principle as a machine would do constructed as Figure
the First.
To shew how this mechanical principle applies to presses:-A, B, in
Figure 3d, represent the piston of a press made to act upon this new
mechanical principle, C, D, a bar of iron made to act upon the top of the
piston, either horizontally or diagonally; and let there be two blocks or pulleys,
E and F, at cach end of the bar of iron, fitted so as to traverse along the bar,
and let there be two rollers with toothed wheels, and worked by a lever (as was
represented by Figure 2nd), at G, with a rope or chain made fast to them, and
passing through the block at E, and let there be two rollers the same as
G at H, with a rope or chain passing through the block at F, also worked
by a lever; now, it is evident that whatever is below the piston at B, when
the new mechanical power is hove upon at G and at H, that it will be pressed
according to the degree of power in these two machines; and it is also evident
that the same mechanical principle acts upon this machine as was shewn to
act upon the two machines represented by Figures 1st and 2nd.
If the principles by which any or all of the six mechanical powers act on (for
the explanation of which see Enciclopedia Britannica, under the article Mecha-
nicks), either as single powers or as compound powers of each other, be
compared with the principle by which this new mechanical power acts on,
it will be clearly seen that the principles which the six powers act on, or the
compound of these powers, are different from the principle upon which this
new power acts, for it will be found that none of these powers, either single or
compound, cause the weight which is to be lifted to assist in lifting it's self,
which has been demonstrated and shewn that this mechanical power, acting
upon this new principle, has that property of causing the weight which is to be
lifted to assist in lifting itself. Therefore the Patent does apply to all
machines which have or use a power acting upon this new principle, whatever
the machines may be, and by whatever power or force they are worked.
In witness whereof, I, the said John Hotchkis, have hereunto set my
hand and seal, this Fourteenth day of October, in the year of our
Lord One thousand seven hundred and ninety-nine.
JN HOTCHKIS: (L.S.)

page_text: AND BE IT REMEMBERED, that on the same Fourteenth day of October,
in the year of above mentioned, the aforesaid John Hotchkis came before our
Lord the King in His Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained, in form above written.
And also the Specification aforesaid was stamped according to the tenor of the
Statute in that case made and provided.
Inrolled the same Fourteenth day of October in the roar above writton
Inrolled the same Fourteenth day of October in the your above written.