Chapter VI: Devices Utilizing Capillary Attraction and Physical Affinity

Ludeke and Wilckens's Device

In 1864, Johann Ernst Friedrich Ludeke, of London, and Daniel Wilckens, of Surrey, applied for British patent on "Improvements in Motive Power by Capillary Attraction." They describe their invention as follows:

Our invention consists of improvements in motive power by
capillary attraction constructed as follows:

Figure 1 of the accompanying drawings represents in horizontal
section a square case or cistern; this cistern is filled with
water nearly to the top, and two wheels marked _a_, _a_, and
_b_, _b_, are placed in the water in the cistern. By capillary
attraction the water rises between the two wheels marked _x_,
_x_, to a height above the level of the water in proportion to
the distance of the wheels from each other at _x_, _x_. As the
water rises between the wheels marked _x_, _x_, above its level,
the weight of water between the wheels at _x_, _x_, will cause
the wheels to continually revolve.

Figure 2 represents the same as Figure 1, but in a vertical
section. The said power may be obtained by wheels moved on axis,
or by other apparatus by rise and fall in the water by vertical
motion.

The Jurin Device

The device which we have designated "The Jurin Device," was not, in fact, invented by Jurin. James Jurin furnished an account of the invention to The Royal Society of London, and it appears in the reports of that society published in 1720. The invention was by a friend of Jurin's whose name he does not give in the account.

Jurin's account of his friend's invention is as follows:

Some days ago a method was proposed to me by an ingenious friend
for making a perpetual motion, which seemed so plausible, and
indeed so easily demonstrable from an observation of the late Mr.
Hawksbee, said to be grounded upon experiment, that though I am
far from having any opinion of attempts of this nature, yet, I
confess, I could not see why it should not succeed. Upon trial
indeed I found myself disappointed. But as searches after things
impossible in themselves are frequently observed to produce other
discoveries, unexpected by the Inventor; so this Proposal has
given occasion not only to rectify some mistakes into which we
had been led, by that ingenious and useful member of the Royal
Society above named, but likewise to detect the real principle,
by which water is raised and suspended in capillary tubes, above
the level.

My friend's proposal was as follows:

Fig. 1. Let A B C be a capillary siphon, composed of two legs
A B, B C, unequal both in length and diameter; whose longer and
narrower leg A B having its orifice A immersed in water, the
water will rise above the level, till it fills the whole tube
A B, and will then continue suspended. If the wider and shorter
leg B C, be in like manner immersed, the water will only rise to
same height as F C, less than the entire height of the tube B C.

This siphon being filled with water and the orifice A sunk below
the surface of the water D E, my friend reasons thus:

Since the two columns of water A B and F C, by the supposition,
will be suspended by some power acting within the tubes they are
contained in, they cannot determine the water to move one way, or
the other. But the column B F, having nothing to support it, must
descend, and cause the water to run out at C. Then the pressure
of the atmosphere driving the water upward through the orifice A,
to supply the vacuity, which would otherwise be left in the upper
part of the tube B C, this must necessarily produce a perpetual
motion, since the water runs into the same vessel, out of which
it rises. But the fallacy of this reasoning appears upon making
the experiment.

Exp. 1. For the water, instead of running out at the orifice C
rises upwards towards F, and running all out of the leg B C,
remains suspended in the other leg to the height A B.

Exp. 2. The same thing succeeds upon taking the siphon out of
the water, into which its lower orifice A had been immersed, the
water then falling in drops out of the orifice A, and standing
at last at the height A B. But in making these two experiments
it is necessary that A G the difference of the legs exceed F C,
otherwise the water will not run either way.

Exp. 3. Upon inverting the siphon full of water, it continues
without motion either way.

The reason of all which will plainly appear, when we come to
discover the principle, by which the water is suspended in
capillary tubes.

Mr. Hawksbee's observation is as follows:

Fig. 2. Let A B F C be a capillary siphon, into which the water
will rise above the level to the height C F, and let B A be the
depth of the orifice of its longer leg below the surface of the
water D E. Then the siphon being filled with water, if B A be
not greater than C F, the water will not run out at A, but will
remain suspended.

This seems indeed very plausible at first sight. For since the
column of water F C will be suspended by some power within the
tube, why should not the column B A, being equal to, or less
than the former, continue suspended by the same power.

Exp. 4. In fact, if the orifice C be lifted up out of the water
D E, the water in the tube will continue suspended, unless B A
exceed F C.

Exp. 5. But when C is never so little immersed in the water
immediately the water in the tube runs out in drops at the
orifice A, though the length A B be considerably less than the
height C F.

Mr. Hawksbee, in his book of Experiments, has advanced another
observation, namely, that the shorter leg of a capillary siphon,
as A B F C, must be immersed in the water to the depth F C, which
is equal to the height of the column, that would be suspended in
it, before the water will run out of the longer leg.

Exp. 6. From what mistake this has proceeded, I cannot imagine;
for the water runs out at the longer leg, as soon as the orifice
of the shorter leg comes to touch the surface of the stagnant
water, without being at all immersed therein.

Jurin's attitude concerning his friend's discovery is pleasing. He appears to have had better judgment than to rush into print, or herald forth that Perpetual Motion had been accomplished. Indeed, the account as given to the Royal Society was that of an experiment and a failure. Nevertheless, it presents an interesting point. Capillary Attraction, however, creates no new energy. Adhesion is a force, and is often quite a strong force in nature.

If a rod or tube be held by the hand at one end, and the other end inserted in a liquid, it will be observed that in some instances, depending upon the nature of the material of the rod or tube, and the liquid, at the point of contact the liquid will slightly rise in the tube and on the outside edges of the tube. In other instances it will be depressed slightly at the same point. Whether it will be elevated or depressed depends on whether the adhesion of the liquid to the material of which the tube or rod is composed is greater than the cohesion of the particles of the liquid.

If there be a depression it is manifest that the entire surface of the liquid will be slightly elevated by reason of the depression. On the contrary, if the liquid adheres to and creeps slightly upward on the tube or rod, then it is manifest that the surface of the liquid will come to rest slightly lower than though it did not so creep.

The net result finally gets back to the principle of flotation. The immersion or insertion is a little more difficult in the case of depression, and a little easier in the case of elevation. There is no gain or loss of energy. It simply increases in one case, and diminishes in the other case the amount of displacement, with all the resulting mechanical phenomena.

Sir William Congreve

As stated in the preface of this work, pursuit of Perpetual Motion has by no means been confined to mechanics and tradesmen. Many men eminent, and even famous in professions, art and science have devoted much time and thought to the subject. Among such eminent men is to be mentioned Sir William Congreve, of England, a baronet. He was born 1772, and died in 1828. He was an artillerist and an inventor, and was a son of Lieutenant General Sir William Congreve; was distinguished as a military man, as a member of parliament, and as a business man; was an inventor of note, having invented a war rocket, a gun-recoil mounting, a time-fuse, a parachute attachment for rockets, a hydro-pneumatic canal lock sluice, a process for color painting, a new form of steam engine, a method of consuming smoke, a clock which measured time by a ball rolling down an inclined plane, besides other inventions and discoveries. He published a large number of works on scientific subjects.

It is not, therefore, surprising that whatever Sir William Congreve said or did concerning any scientific or mechanical subject should have attracted general attention.

He devised and made a Perpetual Motion Machine, which, like all others, failed to work. We submit that his plan is peculiarly ingenious, and we fail to see how, without a knowledge of the principles of Conservation of Energy, the Congreve idea should not have appealed to any one as reasonable, and its failure puzzling.

An account of the Congreve device and an explanation of his ideas appeared in "The Atlas" in 1827, and the following description is taken from the article appearing in "The Atlas":

The celebrated Boyle entertained an idea that perpetual motion
might be obtained by means of capillary attraction; and, indeed,
there seems but little doubt that nature has employed this force
in many instances to produce this effect.

There are many situations in which there is every reason to
believe that the sources of springs on the tops and sides of
mountains depend on the accumulation of water created at certain
elevations by the operation of capillary attraction, acting in
large masses of porous material, or through laminated substances.
These masses being saturated, in process of time become the
sources of springs and the heads of rivers; and thus, by an
endless round of ascending and descending waters, form, on the
great scale of nature, an incessant cause of perpetual motion, in
the purest acceptance of the term, and precisely on the principle
that was contemplated by Boyle. It is probable, however, that any
imitation of this process on the limited scale practicable by
human art would not be of sufficient magnitude to be effective.
Nature, by the immensity of her operations, is able to allow for
a slowness of process which would baffle the attempts of man in
any direct and simple imitation of her works. Working, therefore,
upon the same causes, he finds himself obliged to take a more
complicated mode to produce the same effect.

To amuse the hours of a long confinement from illness, Sir
William Congreve has recently contrived a scheme of perpetual
motion, founded on this principle of capillary attraction, which,
it is apprehended, will not be subject to the general refutation
applicable to those plans in which the power is supposed to be
derived from gravity only. Sir William's perpetual motion is as
follows:

Let A B C be three horizontal rollers fixed in a frame; _a a a_,
etc., is an endless band of sponge, running round these rollers;
and _b b b_, etc., is an endless chain of weights, surrounding
the band of sponge, and attached to it, so that they must move
together; every part of this band and chain being so accurately
uniform in weight that the perpendicular side A B will, in all
positions of the band and chain, be in equilibrium with the
hypothenuse A C, on the principle of the inclined plane. Now, if
the frame in which these rollers are fixed be placed in a cistern
of water, having its lower part immersed therein, so that the
water's edge cuts the upper part of the rollers B C, then, if the
weight and quantity of the endless chain be duly proportioned to
the thickness and breadth of the band of sponge, the band and
chain will, on the water in the cistern being brought to the
proper level, begin to move round the rollers in the direction
A B, by the force of capillary attraction, and will continue so
to move. The process is as follows:

On the side A B of the triangle, the weights _b b b_, etc.,
hanging perpendicularly alongside the band of sponge, the band
is not compressed by them, and its pores being left open, the
water at the point _x_, at which the band meets its surface,
will rise to a certain height, _y_, above its level, and thereby
create a load, which load will not exist on the ascending side
C A, because on this side the chain of weights compresses the
band at the water's edge, and squeezes out any water that may
have previously accumulated in it; so that the band rises in a
dry state, the weight of the chain having been so proportioned
to the breadth and thickness of the band as to be sufficient to
produce this effect. The load, therefore, on the descending side
A B, not being opposed by any similar load on the ascending
side, and the equilibrium of the other parts not being disturbed
by the alternate expansion and compression of the sponge, the
band will begin to move in the direction A B; and as it moves
downwards, the accumulation of water will continue to rise, and
thereby carry on a constant motion, provided the load at _x y_ be
sufficient to overcome the friction on the rollers A B C.

Now, to ascertain the quantity of this load in any particular
machine, it must be stated that it is found by experiment that
the water will rise in a fine sponge about an inch above its
level; if, therefore, the band and sponge be one foot thick and
six feet broad, the area of its horizontal section in contact
with the water would be 864 square inches, and the weight of the
accumulation of water raised by the capillary attraction being
one inch rise upon 864 square inches, would be 30 lbs., which, it
is conceived, would be much more than equivalent to the friction
of the rollers.

The deniers of this proposition, on the first view of the
subject, will say, it is true the accumulation of the weight on
the descending side thus occasioned by the capillary attraction
would produce a perpetual motion, if there were not as much power
lost on the ascending side by the change of position of the
weights, in pressing the water out of the sponge.

The point now to be established is, that the change in the
position of the weights will not cause any loss of power. For
this purpose, we must refer to the following diagram.

With reference to this diagram, suppose _a a a_, etc., an endless
strap, and _b b b_, etc., an endless chain running round the
rollers; A B C not having any sponge between them, but kept
at a certain distance from each other by small and inflexible
props, _p p p_, etc., then the sides A B and C A would, in all
positions of this system, be precisely an equilibrium, so as
to require only a small increment of weight on either side to
produce motion. Now, we contend that this equilibrium would still
remain unaffected, if small springs were introduced in lieu of
the inflexible props _p p p_, so that the chain _b b b_ might
approach the lower strap _a a a_, by compressing these small
springs with its weight on the ascending side; for although
the centre of gravity of any portion of chain would move in a
different line in the latter case--for instance, in the dotted
line--still the quantity of the actual weight of every inch of
the strap and chain would remain precisely the same in the
former case, where they are kept at the same distance in all
positions, as in the latter case, where they approach on the
ascending side; and so, also, these equal portions of weights,
notwithstanding any change of distance between their several
parts which may take place in one case and not in the other,
would in both cases rise and fall, though the same perpendicular
space, and consequently the equilibrium, would be equally
preserved in both cases, though in the first case they may rise
and fall through rather more than in the second. The application
of this demonstration to the machine described in Fig. 1, is
obvious; for the compression of the sponge by the sinking of
the weights on the ascending side, in pressing out the water,
produces precisely the same effect as to the position and ascent
of the weights, as the approach of the chain to the lower strap
on the ascending side, in Fig. 2, by the compression of the
springs; and consequently, if the equilibrium is not affected in
one case--that is, in Fig. 2, as above demonstrated--it will not
be affected in the other case, Fig. 1; and, therefore, the water
would be squeezed out by the pressure of the chain without any
loss of power. The quantity of weight necessary for squeezing
dry any given quantity of sponge must be ascertained and duly
apportioned by experiment. It is obvious, however, that whether
one cubic inch of sponge required one, two, or four ounces
for this purpose, it would not affect the equilibrium, since,
whatever were the proportion on the ascending side, precisely
the same would the proportion be on the descending side.

This principle is capable of application in various ways, and
with a variety of materials. It may be produced by a single
roller or wheel. Mercury may also be substituted for water, by
using a series of metallic plates instead of sponges; and, as the
mercury will be found to rise to a much greater height between
these plates, than water will do in a sponge, it will be found
that the power to be obtained by the latter materials will be
from 70 to 80 times as great as by the use of water. Thus, a
machine, of the same dimensions as given above, would have a
constant power of 2,000 lbs. acting upon it.

We now proceed to show how the principle of perpetual motion
proposed by Sir William Congreve may be applied upon one centre
instead of three.

In the following figure, _a b c d_ represents a drum-wheel or
cylinder, moving on a horizontal axis surrounded with a band
of sponge 1 2 3 4 5 6 7 8, and immersed in water, so that the
surface of the water touches the lower end of the cylinder. Now
then, if, as in Fig. 2, the water on the descending side _b_
be allowed to accumulate in the sponge at _x_, while, on the
ascending side D, the sponge at the water's edge shall, by any
means not deranging the equilibrium, be so compressed that it
shall quit the water in a dry state, the accumulation of water
above its level at _x_, by the capillary attraction, will be a
source of constant rotary motion; and, in the present case, it
will be found that the means of compressing the sponge may be
best obtained by buoyancy, instead of weight.

For this purpose, therefore, the band of sponge is supposed to
be divided into eight or more equal parts, 1 2 3 4, etc., each
part being furnished with a float or buoyant vessel, _f_ 1,
_f_ 2, etc., rising and falling upon spindles, _s s s_, etc.,
fixed in the periphery of the drum; these floats being of such
dimensions that, when immersed in water, the buoyancy or pressure
upwards of each shall be sufficient to compress that portion of
the sponge connected with it, so as to squeeze out any water it
may have absorbed. These floats are further arranged by means of
levers _l l l_, etc., and plates _p p p_, etc., so that, when
the float _f_ No. 1 becomes immersed in the water, its buoyant
pressure upwards acts not against the portion of the sponge No.
1, immediately above it, but against No. 2, next in front of it;
and so, in like manner, the buoyancy of _f_ No. 2 float acts on
the portion of the sponge No. 3, and _f_ No. 3 float upon No. 4
sponge.

Now, from this arrangement it follows, that the portion of sponge
No. 4, which is about to quit the water, is pressed upon by
that float, which, from acting vertically, is most efficient in
squeezing the sponge dry; while that portion of the sponge No. 1,
on the point of entering the water, is not compressed at all from
its corresponding float No. 8, not having yet reached the edge
of the water. By these means, therefore, it will be seen that
the sponge always rises in a dry state from the water on the
ascending side, while it approaches the water on the descending
side in an uncompressed state, and open to the full action of
absorption by the capillary attraction.

The great advantage of effecting this by the buoyancy of light
vessels instead of a burthen of weights, as in Fig. 2, is that,
by a due arrangement of the dimensions and buoyancy of the floats
immersed, the whole machine may be made to float on the surface
of the water, so as to take off all friction whatever from the
centre of suspension. Thus, therefore, we have a cylindrical
machine revolving on a single centre without friction, and having
a collection of water in the sponge on the descending side,
while the sponge on the ascending side is continually dry; and
if this cylinder be six feet wide, and the sponge that surrounds
it one foot thick, there will be a constant moving power of
thirty pounds on the descending side, without any friction to
counteract it.

It has been already stated, that to perpetuate the motion of
this machine, the means used to leave the sponge open on the
descending side, and press it dry on the ascending side, must
be such as will not derange the equilibrium of the machine when
floating in water. As, therefore, in this case the effect is
produced by the ascent of the buoyant floats _b_, to demonstrate
the perpetuity of the motion, we must show that the ascent of the
floats _f_ No. 1 and _f_ No. 3 will be equal in all corresponding
situations on each side of the perpendicular; for the only
circumstance that could derange the equilibrium on this system,
would be that _f_ No. 1 and _f_ No. 3 should not in all such
corresponding situations approach the centre of motion equally;
for it is evident that in the position of the floats described in
the above figure, if _f_ No. 1 float did not approach the centre
as much as _f_ No. 3, the equilibrium would be destroyed, and the
greater distance of _f_ No. 1 from the centre than that of f No.
3 would create a resistance to the moving force caused by the
accumulation of the water at _x_.

It will be found, however, that the floats _f_ No. 1 and _f_ No.
3 do retain equal distances from the centre in all corresponding
situations, for the resistance to their approach to the centre
by buoyancy is the elasticity of the sponge at the extremity
of the respective levers; and as this elasticity is the same
in all situations, while this centrifugal force of the float
_f_ No. 1 is equal to that of the float _f_ No. 3, at equal
distances from the perpendicular, the floats _f_ No. 1 and _f_
No. 3 will, in all corresponding situations on either side of
the perpendicular, be at equal distances from the centre. It is
true, that the force by which these floats approach the centre
of motion varies according to the obliquity of the spindles on
which they work, it being greatest in the perpendicular position;
but, as the obliquity of these spindles is the same at all equal
distances from the perpendicular, and as the resistance of
the ascent of the floats is equal in all cases, the center of
buoyancy will evidently describe a similar curve on each side
of the perpendicular; and consequently the equilibrium will be
preserved, so as to leave a constant moving force at _x_, equal
to the whole accumulation of water in the sponge. Nor will
this equilibrium be disturbed by any change of position in the
floats not immersed in the water, since, being duly connected
with the sponge by the levers and plates, they will evidently
arrange themselves at equal distances from the center, in all
corresponding situations on either side.

It may be said that the equilibrium of the band of sponge may be
destroyed by its partial compression; and it must be admitted
that the centre of gravity of the part compressed, according
to the construction above described, does approach the center
of motion nearer than the center of gravity of the part not
compressed. The whole weight of the sponge is, however, so
inconsiderable, that this difference would scarcely produce any
sensible effect; and if it did, a very slight alteration in the
construction, by which the sponge should be compressed as much
outwards as inwards, would retain the center of gravity of the
compressed part at the same distance from the center of motion as
the center of gravity of the part not compressed.