Scientific American Supplement, No. 392, July 7, 1883

V >> Various >> Scientific American Supplement, No. 392, July 7, 1883

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I have made numerous other experiments bearing upon the question of
neutrality, but they all confirm those I have cited, which I consider
afford ample evidence of the symmetrical arrangement of neutrality.

SUPERPOSED MAGNETISM.

Knowing that by torsion we can rotate or diminish magnetism, I was
anxious to obtain by its means a complete rotation from north polarity
to neutrality, and from neutrality to south polarity, or to completely
reverse magnetic polarity by a slight right or left torsion.

I have succeeded in doing this, and in obtaining strong reversal of
polarities, by superposing one polarity given while the rod is under a
right elastic torsion, with another of the opposite polarity given under
a left elastic torsion, the neutral point then being reached when the
rod is free from torsion. The rod should be very strongly magnetized
under its first or right-hand torsion, so that its interior molecules
are rotated, or, in other words, magnetized to saturation; the second
magnetization in the contrary sense and torsion should be feebler, so
as only to magnetize the surface, or not more than one-half its depth;
these can be easily adjusted to each other so as to form a complete
polar balance of force, producing, when the rod is free from torsion,
the neutrality as shown at B, Fig. 1.

The apparatus needed is simply a good compound horseshoe permanent
magnet, 15 centimeters long, having six or more plates, giving it a
total thickness of at least 3 centimeters. We need a sufficiently
powerful magnet, as I find that I obtain a more equal distribution of
magnetism upon a rod or strip of iron by drawing it lengthwise over a
single pole in a direction from that pole, as shown in Fig. 2; we can
then obtain saturation by repeated drawings, keeping the same molecular
symmetry in each experiment.

In order to apply a slight elastic torsion when magnetizing rods or
wires, I have found it convenient to attach two brass clamp keys to the
extremities of the rods, or simply turn the ends at right angles, as
shown in the following diagram, by which means we can apply an elastic
twist or torsion while drawing the rod over the pole of the permanent
magnet. We can thus superpose several and opposite symmetrical
structures, producing a polar north or south as desired, greatly in
excess of that possible under a single or even double magnetization, and
by carefully adjusting the proportion of opposing magnetisms, so that
both polarities have the same external force, the rod will be at perfect
external neutrality when free from torsion.

[Illustration: FIG. 2.]

If we now hold one end of this rod at a few centimeters distance from
a magnetic directive needle, we find it perfectly neutral when free
of torsion, but the slightest torsion right or left at once produces
violent repulsion or attraction, according to the direction of the
torsion given to the rod, the iron rod or strips of hoop-iron which
I use for this experiment being able, when at the distance of five
centimeters from the needle, to turn it instantly 90 deg. on either side of
its zero.

The external neutrality that we can now produce at will is absolute, as
it crosses the line of two contrary polarities, being similar to the
zero of my electric sonometer, whose zero is obtained by the crossing of
two opposing electric forces.

This rod of iron retains its peculiar powers of reversal in a remarkable
degree, a condition quite different to that of ordinary magnetization,
for the same rod, when magnetized to saturation under a single ordinary
magnetism, loses its evident magnetism by a few elastic torsions, as I
have already shown; but when it is magnetized under the double torsion
with its superposed magnetism, it is but slightly reduced by variations
or numerous torsions, and I have found it impossible to render this
rod again free from its double polar effects, except by strongly
remagnetizing it to saturation with a single polarity. The superposed
magnetism then becomes a single directive force, and we can then by a
few vibrations or torsions reduce the rod to its ordinary condition.

The effects of superposed magnetism and its double polarity I have
produced in a variety of ways, such as by the electro-magnetic influence
of coils, or in very soft iron simply by the directive influence of
the earth's magnetism, reversing the rod and torsions when held in
the magnetic meridian, these rods when placed magnetic west showing
distinctly the double polar effects.

It is remarkable, also, that we are enabled to superpose and obtain
the maximum effects on thin strips of iron from 1/4 to 1/2 millimeter in
thickness, while in thicker rods we have far less effect, being masked
by the comparatively neutral state of the interior, the exterior
molecules then reaching upon those of the interior, allowing them to
complete in the interior their circle of attractions.

I was anxious to obtain wires which would preserve this structure
against the destructive influence of torsion and vibrations, so that I
could constantly employ the same wires without the comparatively long
and tedious process of preparation. Soft iron soon loses the structure,
or becomes enfeebled, under the constant to and fro torsions requisite
where we desire a constant change of polarity, as described later in the
magnetic bells. Hard steel preserves its structure, but its molecular
rigidity is so great that we obtain but mere traces of any change of
polarity by torsion. I have found, however, that fine cast drill steel,
untempered, of the kind employed by watchmakers, is most suitable;
these are generally sold in straight lengths of 30 centimeters. Wires
1 millimeter in diameter should be used, and when it is desired to
increase the force, several of these wires, say, nine or ten, should be
formed into a single rod or bunch.

The wire as sold is too rigid to give its maximum of molecular rotation
effect. We must therefore give it two entire turns or twists to the
right, and strongly magnetize it on the north pole of the magnet while
under torsion. We must again repeat this operation in the contrary
direction, after restoring the wire to its previous position, giving now
two entire turns to the left and magnetizing it on the south pole. On
restoring the wire to its original place, it will be extremely flexible,
and we may now superpose several contrary polarities under contrary
torsions, as already described.

The power of these wires, if properly prepared, is most remarkable,
being able to reverse their polarity under torsion, as if they were
completely saturated; and they preserve this power indefinitely if not
touched by a magnet. It would be extremely difficult to explain the
action of the rotative effects obtained in these wires under any other
theory than that which I have advanced; and the absolute external
neutrality that we obtain in them when the polarities are changing, we
know, from their structure, to be perfectly symmetrical.

I was anxious to show, upon the reading of this paper, some mechanical
movement produced by molecular rotation, consequently I have arranged
two bells that are struck alternately by a polarized armature put in
motion by the double polarized rod I have already described, but whose
position, at three centimeters distant from the axis of the armature,
remains invariably the same. The magnetic armature consists of a
horizontal light steel bar suspended by its central axle; the bells are
thin wine glasses, giving a clear musical tone loud enough, by the force
with which they are struck, to be clearly heard at some distance. The
armature does not strike these alternately by a pendulous movement, as
we may easily strike only one continuously, the friction and inertia of
the armature causing its movements to be perfectly dead beat when not
driven by some external force, and it is kept in its zero position by a
strong directive magnet placed beneath its axle.

The mechanical power obtained is extremely evident, and is sufficient to
put the sluggish armature in rapid motion, striking the bells six times
per second, and with a power sufficient to produce tones loud enough to
be clearly heard in all parts of the hall of the Society. As this is
the first direct transformation of molecular motion into mechanical
movement, I am happy to show it on this occasion.

There is nothing remarkable in the bells themselves, as they evidently
could be rung if the armature was surrounded by a coil, and worked by an
electric current from a few cells. The marvel, however, is in the small
steel superposed magnetic wire producing by slight elastic torsions from
a single wire, one millimeter in diameter, sufficient force from mere
molecular rotation to entirely replace the coil and electric current.

ELASTIC NATURE OF THE ETHER SURROUNDING THE MAGNETIC MOLECULES.

During these researches I have remarked a peculiar property of
magnetism, viz., that not only can the molecules be rotated through any
degree of arc to its maximum, or saturation, but that, while it requires
a comparatively strong force to overcome its rigidity or resistance to
rotation, it has a small field of its own through which it can move with
excessive freedom, trembling, vibrating, or rotating through a small
degree with infinitely less force than would be required to rotate it
permanently on either side. This property is so marked and general that
we can observe it without any special iron or apparatus.

Let us take a flat rod of ordinary hoop iron, 30 or more centimeters
in length. If, while holding this vertically, we give freedom to its
molecules by torsions, vibrations, or, better still, by a few blows with
a wooden mallet upon its upper extremity, we find, as is well known,
that its lower portion is strongly north, and its upper south. If we
reverse this rod, we now find it neutral at both extremities. We might
here suppose that the earth's directing force had rotated the molecules
to zero, or transversely, which in reality it has done, but only to the
limit of their comparatively free motion; for if we reverse the rod to
its original position, its previous strong polarity reappears at both
extremities, thus the central point of its free motion is inclined to
the rod, giving by its free motion great symmetrical inclination and
polarity in one direction, but when reversed the inclination is reduced
to zero.

In Fig. 3, D shows the bar of iron when strongly polarized by earth's
magnetic influence, under vibrations, with a sufficient force to have
rotated its elastic center of action. C shows the same bar with its
molecules at zero, or transversal, the directing force of earth being
insufficient without the aid of mechanical vibration to allow them to
change. The dotted lines of D suppose the molecule to be in the center
of its free motion, while at C the molecules have rotated to zero, as
they are prevented from further rotation by being at the extreme end of
its free motion.

If, now, we hold the rod vertically, as at C, giving neutrality, and
give a few slight blows with a wooden mallet to its upper extremity, we
can give just the amount of freedom required for it to produce evident
polarity, and we then have equal polarity, no matter which end of the
bar is below, the center of its free rotation here being perfect, and
the rod perfectly neutral longitudinally when held east and west. If, on
the other hand, we have given too much freedom by repeated blows of the
mallet, its center of free motion becomes inclined with the molecules,
and we arrive at its first condition, except that it is now neutral at
D and polarized at C. From this it will be seen that we can adjust
this center of action, by vibrations or blows, to any point within the
external directing influence.

[Illustration: FIG. 3.]

We can perceive this effect of free rotation in a limited space in all
classes of iron and steel, being far greater in soft Swedish iron than
in hard iron or steel. A similar phenomenon takes place if we magnetize
a rod held vertically in the direction of earth's magnetism. It
then gives greater polarity than if magnetized east or west, and if
magnetized in a contrary sense to earth's magnetism, it is very feebly
magnetized, or, if the rod is perfectly soft, it becomes neutral after
strong magnetization. This property of comparative freedom, and the
rotation of its center of action, can be demonstrated in a variety of
ways. One remarkable example of it consists in the telephone. All those
who are thoroughly acquainted with electro-magnetism, and know that
it requires measurable time to charge an electro-magnet to saturation
(about one-fifteenth of a second for those employed in telegraphy),
were surprised that the telephone could follow the slightest change of
timbre, requiring almost innumerable changes of force per second. I
believe the free rotation I have spoken of through a limited range
explains its remarkable sensitiveness and rapidity of action, and,
according to this view, it would also explain why loud sounding
telephones can never repeat all the delicacy of timbre that is easily
done with those only requiring a force comprised in the critical limits
of its free rotation. This property, I have found, has a distinct
critical value for each class of iron, and I propose soon to publish
researches upon the molecular construction of steel and iron, in which
I have made use of this very property as a guide to the quality of the
iron itself.

The elastic rotation (in a limited space) of a molecule differs entirely
from that known as mechanical elasticity. In perfectly soft iron we have
feeble _mechanical_ elasticity, while in tempered steel we have
that elasticity at its maximum. The contrary takes place as regards
_molecular_ elasticity. In tempered steel the molecules are extremely
rigid, and in soft iron its molecular elasticity is at its maximum. Its
free motion differs entirely from that given it by torsion or stress. We
may assume that a molecule is surrounded by continuous ether, more of
the nature of a jelly than of that of a gas; in such a medium a molecule
might freely vibrate through small arcs, but a rotation extending beyond
its critical limit would involve a much greater expenditure of force.

The discovery of this comparatively free rotation of molecules, by means
of which, as I have shown, we can (without in any degree disturbing the
external mechanical elasticity of the mass) change the axes of their
free motion in any direction desired, has led me into a series of
researches which have only indirectly any relation with the theory of
magnetism. I was extremely desirous, however, of finding an experimental
evidence which in itself should demonstrate all portions of the theory,
and the following experiment, I believe, answers this purpose.

Let us take a square soft iron rod, five millimeters in diameter by
thirty or more centimeters in length, and force the molecules, by aid
of blows from a wooden mallet, as previously described, to have their
centers of free motion in one direction; the rod will (as already shown)
have polarity at both ends, when held vertically; but if reversed, both
ends become completely neutral.

If now we turn the rod to its first position, in which it shows strong
polarity, and magnetize it while held vertically, by drawing the north
pole of a sufficiently powerful permanent magnet from its upper to its
lower extremity, we find that this rod, instead of having south polarity
at its lower portion, as we should expect from the direction of the
magnetization, is completely neutral at both extremities, but if we
reverse the rod its fullest free powers of magnetization now appear in
the position where it was previously neutral. Thus, by magnetization, we
have completely rotated its free path of action, and find that we can
rotate this path as desired in any direction by the application of a
sufficient directing power.

If we take a rod as described, with its polarities evident when held
vertically, and its neutrality also evident when its ends are reversed
in the same magnetic field, we find that its polarity is equal at both
ends, and that it is in every way symmetrical with a perfect magnet. If
we _gradually_ reverse the ends and take observations of its condition
through each degree of arc passed over, we find an equal symmetrical
diminution of evident external polarity, until we arrive at neutrality,
when it has no external trace of inherent polarity; but its inherent
polarity at once becomes evident by a simple return to its former
position. Thus the rod has passed through all the changes from polarity
to neutrality, and from neutrality to polarity, and these changes have
taken place with complete symmetry.

The limits of this paper do not allow me to speak of the numerous
theoretical evidences as shown by the use of my induction balance. I
believe, however, that I have cited already experimental evidences to
show that what has been attributed to coercive force is really due to
molecular freedom or rigidity; that in inherent molecular polarity we
have a fact admitted by Coulomb, Poisson, Ampere, De la Rive, Weber,
Du Moncel, Wiedermann, and Maxwell; and that we have also experimental
evidence of molecular rotation and of the symmetrical character of
polarity and neutrality.

The experiments which I have brought forward in this paper, in addition
to those mentioned in my paper read before the Royal Society, will,
I hope, justify me in having advanced a theory of magnetism which I
believe in every portion allows at least experimental evidences of its
probable truth.

* * * * *

THE WESTINGHOUSE BRAKE.

Below we illustrate the main parts of the Westinghouse brake as applied
to a vehicle. The supplementary reservoir brake cylinder and triple
valve are shown in position, and as fitted upon the engine, tender, and
each vehicle of the train. Air compressed by a pump on the locomotive
to, say, 70 lb. or 80 lb. to the square inch fills the main reservoir on
the engine, and flowing through the driver's brake valve and main pipe,
also charges the supplementary reservoirs throughout the train. When
a train is running, uniform air pressure exists throughout its
length--that is to say, the main reservoir on the engine, the pipe from
end to end of train, the triple valves and supplementary reservoirs on
each vehicle, are all charged ready for work, the brake cylinders being
empty and the brakes off. The essential principle of the system is,
that maintaining the pressure keeps the brakes off, but letting the air
escape from the brake pipe, purposely or accidentally, instantly applies
them. It follows, therefore, that the brake may be applied by the driver
or any of the guards, or if necessary by a passenger, by the separation
of a coupling, or the failure or injury to a vital part of the
apparatus, whether due to an accident to the train or to the brake; and
as the brake on each vehicle is complete in itself and independent,
should the apparatus on any one carriage be torn off, the brake will
nevertheless remain applied for almost any length of time upon the rest
of the train.

The triple valve, as will be seen, is simply a small piston, carrying
with it a slide valve, which can be moved up or down by increasing or
decreasing the pressure in the brake pipe. As soon as the air from the
main reservoir is turned into the brake pipe, by means of the driver's
valve, the piston is pushed up into the position shown, and air is
allowed to feed past it through a small groove into the reservoir. At
the same time the slide valve covers the port to the brake cylinder, and
is in such a position that the air from the latter may exhaust into the
atmosphere. The piston has now the same air pressure on both sides; but
if the pressure in the brake pipe is decreased, the piston and slide
valve are forced down, thereby uncovering the passage through which air
from the reservoir flows into the brake cylinder between the pistons,
thus applying the brakes. The brake pipe is shut off as soon as the
triple valve piston passes the groove. To release the brakes, the piston
and slide valves are again moved into the position shown, by the driver
turning air from the main reservoir into the brake pipe. The air in the
brake cylinder escapes, and at the same time the reservoir is recharged.

[Illustration: THE WESTINGHOUSE BRAKE.]

Fig. 2 represents two Westinghouse couplings connected. They are exactly
alike in all respects, and an air tight joint is made between them by
means of the rubber washers. These couplings are so constructed that the
air pressure within serves to tighten the joint, and they may be pushed
apart by the separation of the train without any injury. Such an
occurrence as already explained leads to the instant application of all
the brakes on the train.

By closing the small tap shown between the brake pipe and the triple
valve, the brake on any vehicle, if out of order, can be cut out of the
system. A release valve is also placed upon each cylinder as shown, so
that in the event of the brakes being applied by the separation of
the train, or the breaking of a pipe, or when the locomotive is not
attached, they can be released by allowing the air to escape from each
brake cylinder direct. The Westinghouse brake has been made to comply
thoroughly with the Board of Trade conditions. Many people, however, do
not appear to understand all that is involved in the second requirement,
which runs as follows: In case of accident, to be instantaneously
self-acting. This clearly implies: First, that accident to the train,
or to any of its vehicles, shall cause the instant application of
the brakes to the wheels of every vehicle in the train without the
intervention of the driver or guards. Secondly, that any injury, however
caused, which may impair the efficiency of the brake apparatus, shall,
in like manner, lead to the instant application of all the brakes on
the train. It then becomes impossible for a driver to run his train in
ignorance of any defect in his brake apparatus because such defect at
once discloses itself by applying the brakes and stopping the train.
Thirdly, that each vehicle shall carry its own brake power in such a
manner that the destruction of the brake apparatus on one or more of the
carriages shall not affect the efficiency of the brakes upon any of the
others. No continuous brake which does not comply with such conditions
can ever be satisfactory.--_The Engineer_.

* * * * *

HYDRAULIC ELEVATORS AND MOTORS.

[Footnote: Read at Buffalo meeting of the American Water-Works
Association May 15,1883.]

By B. F. JONES, Kansas City.

What I have to say in relation to elevators and motors will be mostly in
regard to questions that their uses necessarily bring up for settlement
at the water-works office; also to show how I have been able in a
measure to overcome some of the many difficulties that have presented
themselves, as well as to discuss and seek information as to the best
way of meeting others that still have to be dealt with. At the outset,
therefore, let me state that I am not an hydraulic engineer, nor have
I sufficient mechanical knowledge to undertake the discussion of the
construction or relative merits of either elevators or motors. This I
would respectfully suggest as a very proper and interesting topic for a
paper at some future meeting by some one of the many, eminent engineers
of this association.

The water-works of Kansas City is comparatively young, and my experience
only dates back six or seven years, or shortly after its completion.
At this time it was deemed advisable on account of the probable large
revenue to be derived from their use, to encourage the putting in of
hydraulic elevators by low water rates. With this end in view a number
of contracts were made for their supply at low special rates for a
period of years, and our minimum meter rate was charged in all other
cases, regardless of the quantity of water consumed. In most instances
these special rates have since been found much too low, parties paying
in this way being exceedingly extravagant in the use of elevators.
However, the object sought was obtained, and now they are very
extensively used. In fact, so much has their use increased, that the
question is no longer how to encourage their more general adoption, but
how to properly govern those that must be supplied. A present our works
furnish power to about 15 passenger and 80 freight elevators, and the
number is rapidly increasing.

Before going into details it seems proper to give at least a brief
description of our water-works, as my observations are to a great extent
local.

On account of the peculiar topography of Kansas City (and I believe it
has more topography to the square foot than any city in the country)
two systems of water supply have been provided, the high ground being
supplied by direct pumping, and a pressure of about 90 pounds maintained
in the business portion, and the lower part of the city being supplied
by gravity, from a reservoir at an elevation of 210 feet, thus giving
the business portions of the city, on high and low ground, about the
same pressure. By an arrangement of valves, a combination of these
two systems is effected, so that the Holly machinery can furnish an
increased fire pressure at a moment's notice, into either or both pipe
systems. Thus at some points the pressure is extremely high during the
progress of fires, causing difficulties that do not exist where the
gravity system of works is used exclusively.

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