Chapter V: Magnetic Devices

A Magnetic Pendulum

Here we present a device for Perpetual Motion by magnetism, but we are unable to give the inventor's name or his nativity. It seems to have been brought forth in the early part of the nineteenth century, prior to 1828. The description is as follows:

Let A A, in the prefixed engraving, represent two magnets
revolving on axes. Let B represent a larger magnet, hanging on
an axis, pendulum fashion, between the two former. As the poles
of the two smaller magnets lie in the same direction, the effect
will be to draw the larger magnet towards that on the left hand,
while it is at the same time repelled by that on the right; but
while this is going on, the upper end of the large magnet raises
by means of a guide wire, the tumbler D, which, just before the
magnets come in contact, passes the perpendicular and falls over,
carrying with it the lever connected with the two wheels C C, and
causing them to perform a quarter revolution; these wheels are
connected by lines with two small wheels fixed on the axles of
the two magnets A A. While the former make a quarter revolution,
the latter turn half round; consequently, the position of the
magnets is reversed, and the same motions are then performed by
the pendulum magnet being attracted and repelled in the opposite
direction; and just before the magnets touch each other the
arrangement is again instantly reversed.

Magnetic-Driven Wheel

Another plan for Perpetual Motion by magnetism appeared in the public journals of England in 1828. The inventor states in effect that he desires to get before the readers an

"Attempt at Perpetual Motion by Means of Magnetism, Applied in a New Way."

His attempt as published is as follows:

The object of the present communication is to lay before your
readers an attempt at perpetual motion by means of magnetism
applied somewhat differently to any that has yet been published
in your Magazine.

The above is a wheel of light construction, moving on friction
wheels _in vacuo_; the rim is furnished with slips of
steel--pieces of watch-spring will do. N N are two magnets,
which, attracting the rim of the wheel, will render one side
lighter and the other heavier, causing it to revolve _ad
infinitum_: or to render it more powerful, let the steel rims
be magnetized and fixed on the wheel with their north poles
towards its center. Let two more magnets be added, as shown by
the dotted lines: let these two, S S, be placed with their south
poles nearest the rim of the wheel; and the other two, N N, with
their north poles in that position. Now, as similar poles repel
and opposite poles attract, the wheel will be driven round by
attraction and repulsion acting conjointly on four points of its
circumference. B B are blocks of wood to keep off the attraction
of the magnets from that part of the wheel which has passed them.

Mackintosh's Experiment

F. S. Mackintosh, of England, in 1823, sought to accomplish Perpetual Motion, and made the attempt here described. It was not made public until 1836, when it was published in "Mechanics' Magazine." In the meantime, the inventor had become convinced of the impossibility of perpetual motion, as his comments on his own alleged invention discloses.

(The classification in this book of Mackintosh's invention is somewhat doubtful. The article as contributed in 1836 would as aptly be classified under arguments against Perpetual Motion, Chapter XII. But, in view of the fact that at the time of the invention the inventor was seriously working at a scheme for the accomplishment of Perpetual Motion, it has been decided to classify it under Magnetic Perpetual Motion Devices.)

The published article was in the nature of a contribution from the inventor, and is as follows:

I herewith forward you a description of a machine which was
constructed by me in the year 1823, with a view to produce a
perpetual motion. With this machine and the studies necessarily
connected with it, first originated the suspicion that the
planets could not continue in motion unless they gradually
approached the center of the attraction.

In the first place, let us describe the machine. Fig. 1: A is
a sectional view of the interior of the wheel, which is formed
in two halves upon one shaft; each half or section is furnished
with a projecting ledge and an opening is left between the two
ledges sufficiently wide to admit of a magnet being introduced
between them, by which arrangement the magnet may be brought as
near to the ball as may be necessary (see Fig. 2). B is a magnet
whose line of attraction acts at right angles with the line of
gravity. C is an iron ball under the action of two forces. The
magnet continually drawing the ball up the inclined plane within
the wheel, and gravity continually drawing it to the bottom,
by their united action it was supposed the wheel would revolve
forever, or till it was worn out; upon the same principle that a
wheel revolves by the animal force or muscular action of a mouse
or squirrel, which carries it up the inclined plane, whilst it is
continually drawn to the bottom by the action of gravity, thereby
causing the wheel to revolve by the weight of its body. The
model was taken from the earth's motion round the sun; and the
following process of reasoning seemed to justify the assumption
that the wheel would move on till it was worn out:

"The earth is carried round the sun by the action of two forces,
one of which is momentum, which is not, in reality, a force
or cause of motion, but an effect derived from an original
impulse; and that impulse or the momentum derived from it is
not destroyed, because there is no resistance to the moving
body--that is, there is no friction. Well, I cannot make this
machine without having resistance to the motion--that is,
friction; but to compensate for this I have two real forces, two
causes of motion, each of them capable of imparting momentum to
a body: they are both constant forces; and from one of them,
the magnet, I can obtain any power that may be required within
certain limits."

This reasoning appeared conclusive, and the wheel was made; but
when the magnet was applied instead of the ball rolling up the
inclined plane, the wheel moved backwards upon its center. It
occurred to me that by placing a small ratchet upon the wheel,
as shown at D, this backward motion of the wheel on its center
might be prevented, in which case the ball must roll up the
inclined plane, and that a perpetual motion might then ensue;
but this ratchet I never tried, having about that time begun to
perceive that the idea of a perpetual mechanical motion, either
on the earth or in the heavens, involves an absurdity; and that,
therefore, the motions of the planets must necessarily carry them
continually nearer and nearer to the center of attraction.

The above described device by Mr. Mackintosh brought forth the following comment from R. Munro, which was published in 1836:

The result of Mr. Mackintosh's essay at perpetual motion might
be attributed to the avoidable friction caused by the manner in
which the iron ball is placed in the wheel. Curious to try the
experiment, I proceeded, and, with the view of diminishing the
friction, I placed two wheels on the axis of the ball, but the
result was precisely that described by Mr. Mackintosh. I next
applied the ratchet, as suggested, but with no better effect; the
ball rolled towards the magnet, but did not give the required
motion to the wheel. It is not unlikely, then, that the present
ingenious attempt will not be realized.

Spence's Device

John Spence, of Linlithgow, Scotland, was a shoemaker, but possessed great mechanical ingenuity. He could not keep his mind from the subject of mechanics. He devoted a great deal of time to designing mechanical schemes for Perpetual Motion. An account of his efforts is taken from "Percy Anecdotes."

The device was exhibited in Edinburgh and amazing to state it attracted the attention of one of the greatest and most original scientists that ever lived, Sir David Brewster.

It is from a letter written by Brewster, in 1818, to the "Annales de Chimie," that we get a description of the Spence invention. The editor of "Annales de Chimie," was evidently reluctant to publish any article concerning Perpetual Motion, and only the great fame of Sir David induced him to give space to the contribution. The article was first published in France, but it has, with an introductory statement by the editor, been translated into English, as follows:

The reader will readily conclude that in publishing this article
we are influenced solely by the great reputation of the learned
contributor. Sir David writes from Edinburgh:

I am almost afraid to inform you that at this moment in Edinburgh
may be seen a machine, made by a shoemaker at Linlithgow, which
realizes the perpetual motion. This effect is produced by two
magnets A and B, acting alternately upon a needle _m n_, of which
the point of attachment _n_ corresponds exactly with the axis
around which turns the movable lever C D. When the needle _m n_
has been attracted into the position _m´ n_ by the action of the
magnet B, and C D is in consequence found in C´ D´, a _substance_
connected with m n is interposed by mechanism between _m´ n_ and
B. This substance has the property of intercepting, or rather of
modifying the action of the magnet B, and this permits the other
magnet A to draw the needle into the position _m´´ n_; but no
sooner has it reached this point than a second plate or layer of
the same substance places itself before magnet, and immediately B
attracts anew the needle.

The annexed figure exhibits a second form of the machine. A
and B are two horse-shoe magnets, _a_ and _b_ the _mysterious
substance_, and _m n_ the needle, which turns constantly with
great rapidity. Mr. Playfair and Capt. Kater have inspected
both of these machines, and are satisfied that they resolve the
problem of _perpetual motion_.

Joannis Theisneri's Semi-Circle

An account of this invention has been preserved by Gaspar Schott in a work entitled "Thaumaturgus Physicus, sive Magiae Universalis Naturae et Artis," published in 1859. It is illustrated by the following figure:

The inventor expected the operation of his device to be as follows: "A" is a large magnet, elevated on a short pillar at the foot of which is a straight inclined tube, "C" "F" the ends of which are connected with a curved or semicircular tube "C", "D", "E", "F", as shown in the figure.

The weight at the lower extremity is supposed to ascend through the curved tube by the attraction of the magnet "A" and upon reaching the point "C" the supposition was that upon passing the point "C" the attraction of the magnet "A" would be sufficient to hold it there * * * back to the point "F" through the straight tube, and then be drawn by the magnet through the curved tube to the point "C" and so on perpetually.

The impracticability of the above device is manifest. At a point between "D" and "E" it is plain the ball would have to ascend perpendicularly and if the magnet exerts sufficient attraction to elevate the weight at that point it would surely hold the weight at the point "C", for at "C" the weight would be much nearer the magnet and consequently much more strongly attracted.

Device of Dr. Jacobus

In the same work by Gaspar Schott from which an account of the preceding device is obtained he gives an account of the device of Dr. Jacobus.

Dr. Jacobus's scheme is illustrated by the following figure:

It will be observed that the above figure shows a string of iron balls "A" suspended on a grooved wheel "E" on an axle "C" between two uprights "FF". At "H" lies a large lodestone, which is to attract the balls at "D" and was expected by the inventor to cause the wheel to rotate.