_a._ To substitute a hair of a mare for the suspending media
above-named.
_b._ To hold a sovereign in the left hand.
_c._ To apply the forefinger of the left hand to the odometer finger.
_d._ To have either hand of a person of the same sex laid on your
right hand or right ear.
_e._ To have either hand of a person of the opposite sex laid upon
your left hand or left ear.
The various substances employed as Od-subjects admit of being divided
into two great classes; one consisting of unorganized or organized
bodies in which a minimum of internal activity is present; the other,
of bodies of both classes, in which the more energetic properties of
matter are at work.
* * * * *
I. Let me first notice the results obtained with the first class of
bodies. These, again, are reducible to two forms. The Od-subject may
either be of a regular figure and equal thickness throughout—as a piece
of money, for instance; or it may be of an irregular figure, with an
unequal mass of matter at one part—as, for instance, when it consists
of an aggregate of several pieces of money variously arranged. I shall
first treat of the first and simpler case.
* * * * *
It does not matter how you face in making these experiments. The
influence of your person makes the various meridians of the Od-subject.
The movements which we have first to examine are the results of holding
the odometer over the middle of various uniform discs, such as I have
supposed. They consist of two series of oscillations—one directed
longitudinally to and from the experimenter; the other transversal,
or in a plane at right angles to the plane of the first series of
oscillations. Then it is highly convenient to have terms denoting
the four cardinal points at which these oscillations cut the edge of
the circular disc. These points may be termed _distal_, _proximal_,
_dextral_, _sinistral_. It will likewise be found convenient to have
terms to denote the direction of the motions manifested. The terms
_distad_, _proximad_, _dextrad_, _sinistrad_, will serve our purpose.
These terms refer to the person of the experimenter. Two other terms
are still wanting; sometimes rotatory motion supervenes, which maybe
either in the direction of the motion of the hands of a watch, or the
reverse. I call the first of these two motions _clock-rotation_, the
second _versed-rotation_.
The present class of Od-subjects present the following remarkable
differences among themselves:—
Over one class, including gold, zinc, and polished glass, a circular
mass of bicarbonate of soda, the odometer primarily oscillates
_longitudinally_.
With the other class, which includes pearl, ground glass, copper, a
circular mass of tartaric acid, the odometer held over the centre
primarily oscillates _transversely_.
Over polished glass, an odometer of resin oscillates transversely; over
ground glass longitudinally.
Each of these movements is replaced by the other, when the thumb is
brought into contact with the odometer-finger. (See figs. 1 and 2, in
which the continuous line represents the primary motion; the dotted
line, the secondary or complementary or reversed motion.)
* * * * *
II. Analysis of the forces, or currents conducing to, or implicated in
the movements of the odometer just described.
It has been said that the above movements manifest themselves when the
odometer is held over the centre of the Od-subject. Let us now examine
the consequences of holding the odometer extra-marginally to, or beyond
the edge of, the Od-subject.
[Illustration: Diagram showing figs. 1-8]
[Illustration: Diagram showing figs. 9-14]
_a._ Let the odometer be held a quarter of an inch away from, and
over each cardinal point of a sovereign, or zinc circular disc,
in succession. _Result_—Held near the distal point, its motion is
_proximad_. Held near the proximal point, its motion is _proximad_.
Held near the dextral point, its motion is _sinistrad_. Held near the
sinistral point, its motion is _sinistrad_. (See fig. 3.)
But the first two impulses thus attained correspond with the direction
of the primary oscillations of the odometer, the last two with its
complementary oscillations; and if the odometer be held now over
different points in succession of the two diametral lines, suspended,
of course, by the finger alone over the first series of points, and
by the finger touched by the thumb over the second, it will be found
that the primary oscillations originated over every point of the
longitudinal diameter of the zinc disc are proximad; and that those
obtainable over any part of the transverse diameter of the zinc disc
are sinistrad.
Then the forces or currents are made manifest by which the two sets of
oscillations are produced; and the marvel of the prompt substitution
of one for the other is at an end; for it is evident that these
two forces, whether produced or only revealed by the presence of
the odometer, co-exist; and that the changed Od-relations of the
experimenter to the odometer, (effected by disjoining the thumb from,
or joining it to, the forefinger,) simply act by giving temporary
predominance to one of the two co-existent currents.
If these experiments be made at the edge of the copper disc, they
elicit opposite but parallel results. (See fig. 4.) They evince the
existence of two currents, one _dextrad_, the other _sinistrad_, from
which the same conclusions may be deduced.
It is important to notice, that in all this class of the experiments,
the distad and dextrad currents are manifested in combination; and in
like manner the proximad and sinistrad.
This combination is further exemplified in the next experiment, which I
shall describe.
_b._ Excite the above extra-marginal motions of the odometer held
near the two plates in succession; and then apply the thumb to the
finger in each experiment. _Result_—Tangential motions are manifested
parallel to the diametral motions before displayed. (See figs. 5 and
6.)
We cannot, however, suppose these extra-marginal tangential motions
to be the lateral limits of the four great currents, inasmuch as they
are obtained by the versed process to that which obtains the central
motion; and the question arises, what then are the limits of the
central currents?
_c._ Hold the odometer over the zinc disc at its centre; of course,
longitudinal oscillations determined by the proximad current manifest
themselves. Then shift its place on the transverse diameter more and
more to the left. _First Result_—For something more than a quarter of
the whole diameter, the motion continues longitudinal, proving that
the central current has a breadth at least something exceeding half
the diameter. Same result on the other side of the centre. _Second
Result_—When the odometer nears the sinistral cardinal point of
the zinc disc, its longitudinal proximad motion is replaced by the
motion I have called clock-rotation. When it is held near the dextral
cardinal point, versed rotation manifests itself.
This second result establishes that the longitudinal proximad current
extends laterally to the edges of the disc; but that, when near to
them, the force of the co-existing transverse current asserts itself,
driving the odometer (on the left) off in a sinistro-proximad diagonal,
which ends in the establishment of clock-rotation; on the right driving
the central current off, in a dextro-proximad diagonal, resulting in
versed rotation. (See fig. 7.)
Parallel and opposite results are obtained by the odometer when these
experiments are repeated with the copper disc; and necessarily the
clock-rotation appears near the proximad margin of the disc, the versed
rotation near the distal edge.
Therefore it is evident that the great longitudinal and transverse
currents extend over the whole disc, but not beyond it. Experiment _a_,
section II., and figs. 3 and 4, show that, immediately beyond the
cardinal points, single forces are in operation.
Other interesting results follow from trying with the odometer the
extra-marginal spaces between the cardinal points.
_d._ First let the central points between each pair of cardinal points
be tried with the zinc disc. _Result_—(see fig. 9,)—a dextro-proximad
current is manifested between the sinistral and distal points, and
between the proximal and dextral points; a sinistro-proximad current
is manifested between the dextral and distal, and between the proximal
and sinistral points—giving the impression that there exist two
diagonal forces, comparable to the longitudinal and transverse forces.
Fig. 10 gives the corresponding, but opposite, results obtained upon
the copper disc.
It is, however, doubtful whether these currents traverse the whole
disc. For if the experiment is made of following each upon the disc,
their influence disappears at less than a quarter of the diameter,
where the odometer is found to obey on the zinc disc the proximad
current, on the copper disc the dextrad current. Or, probably, these
currents are the simple expression of the action of two equal forces
moving the body operated on by them (at right angles to each other)
in the diagonal. These effects thus form a remarkable contrast with
the results given in figs. 7 and 8, wherein rotatory movements are
manifested; and they seem to show that an essential element in these
rotatory movements is, that one of the two currents acting on the
odometer must, in the latter case, be of superior force to the other.
_e._ Repeat the last experiments versed, or with the thumb applied to
the forefinger. _Results_—(see figs. 11 and 12)—Tangential forces are
developed, the directions of which are opposite, as obtained over the
zinc and over the copper discs.
_f._ Repeat the extra-marginal trials of the odometer in all the
halves of the inter-cardinal spaces, both with the zinc and with the
copper discs. (See figs. 13 and 14.) _Result_—A complicated series of
rotatory movements, eight for each disc; four in each case showing
clock-rotation—four versed rotation—but opposite in the corresponding
spaces of the two discs. On applying the thumb to the odometer finger,
the rotations become exactly inverted so that, in that case; fig. 14
represents what is now manifested in the zinc disc, fig. 13 what is
now manifested in the copper disc.
III. Motions of the odometer obtained over the same class of
substances, when of irregular figure and unequal thickness.
_a._ Let the odometer be held over the middle of a line of four
sovereigns disposed either longitudinally, transversely, or obliquely.
_Result_—Long oscillations over the axis of the line of sovereigns.
But the oscillations are not of equal length. At one end of the line
they extend to the edge of the fourth sovereign. At the other, they
pass an inch beyond it.
_b._ Repeat the experiment, touching the odometer-finger with the
right thumb. _Result_—Axial oscillations as before, and unequal as
before, but in the contrary direction.
_c._ Dispose four sovereigns in a line; then place two others upon any
one of the four, and hold the odometer over the table at three inches
to one side of the middle of the line. _Result_—The odometer swings
in each instance towards that sovereign on which the two additional
are placed—but unequally. We will suppose that it has swung with
sufficient strength to reach the disc of the loaded sovereign,—the
oscillation in the contrary direction is but two inches in length.
_d._ Repeat the experiment, with the thumb applied.
_Results_—Oscillations ensue of the same length, and they are again
unequal, but in the contrary direction. Now they do not reach the pile
of sovereigns by an inch, but they pass three inches in the opposite
direction.
[Illustration: Diagram showing figs. 15-24]
[Illustration: Diagram showing fisg 25-29]
Thus a force is brought into view having this new quality: when the
Od-relations of the experimenter are versed, a change ensues, not into
motion in a plane transverse to the former one, but the direction of
the new motion is simply the opposite of the first, or the odometer
appears to be attracted or repelled towards the Od-subject alternately.
_e._ Try the same experiment with a single sovereign, or with the zinc
disc. _Result_—The odometer held at four inches distance is attracted
and repelled just as in the preceding instance.
Then an irregular form of the Od-subject, or its unequal mass at
different parts, have nothing to do with this new motion; and it
is evident that the relation of the latter to the former class of
oscillatory motions will be easily determinable.
_f._ Lay the proper disc before you (see fig. 15,) and hold the
odometer over the production in each direction of its transversal line
beyond the limits of the disc. _Results_—When held near the right edge
of the disc, as before mentioned, a dextrad motion is developed; that
is to say, the odometer moves off from the dextral cardinal point of
the disc, oscillatively. This movement, or those oscillations outward,
are fainter and fainter, as the odometer is held over points more and
more remote from the disc. At length, at the distance of an inch and a
half, the odometer becomes absolutely stationary. When moved, however,
still farther off, motion begins again, which is very lively at four
to five inches distance from the disc, its direction being sensibly
toward the disc. Moved farther off, still the same motion continues,
and is detectable ten to twelve inches off the Od-subject.
When the same experiments are made on the left edge of the Od-subject,
phenomena just the reverse are manifested for the same distance. The
extra-marginal dextrad motion is transverse for an inch and a half.
Then there occurs a point of quiescence; on the other side of which
the odometer swings in free and long sinistrad or repelled oscillations.
_g._ Repeat these experiments (fig. 16,) with the thumb applied.
_Result_—On the left side the near extra-marginal dextrad motion
is replaced by a tangential proximad motion; and the centrifugal
oscillations beyond the point of quiescence are replaced by
centripetal oscillations. On the right side again, the near dextrad
extra-marginal oscillations are replaced by a proximad tangential
current: while beyond the point of quiescence, the remote centripetal
oscillations are reversed into centrifugal ones.
Effects parallel to these are attained at each of the cardinal and
inter-cardinal points of the whole circumference, upon the zinc or
copper disc, but as usual always reversed.
Opposite to the eight intervening spaces, the character of the remote
motion is changed. _There_ it is a rotatory motion in a direction the
reverse of the rotatory motion shown in figs. 15 and 16.
Thus, there exists all round the disc, at a distance of about an inch
and a half, a circle of complete repose. Within this the proper, or
near, extra-marginal movements of the odometer are manifested: without
it, the motions of the second and remote force last described.
But to return to the facts mentioned at the beginning of this section.
The movements of the odometer over a line of sovereigns, or from a
distance towards its centre of gravity, are evidently the consequences
of this remote force coming into operation; the long and forcible
oscillations caused by which toward or from a remote point override
the smaller near extra-marginal, and the super-discal forces of the
Od-subject.
IV. I have next to deal with the effects obtained by trying the
odometer with mineral bodies, in which electric, chemical, or magnetic
forces are energizing, or that force on which crystalline structure
depends, and with organized bodies in possession of life.
In this section, I propose to describe the simple resultants, analogous
to the two diametral movements, obtained when the odometer is held
over a sovereign. It will be remembered that, of these two, one only
manifested itself at a time; and that their meridians were determined
by the person of the experimenter. One movement was either in the
direction of the mesial plane of his person, or in one parallel to
it—namely, the longitudinal oscillations; the other was in a plane at
right angles to the first.
The corresponding movements of the odometer with the class of bodies
now to be considered are rotatory; and two, at least, are always
simultaneously manifested—one a clock rotation, the other a versed
rotation. These opposite rotations are likewise always manifested on
opposite sides or opposite ends of the Od-subject, indicating the
development of polarity. Finally, the force of this polarity is such as
to render the influence of the person of the experimenter nugatory as
to the direction of the forces. Accordingly, if a horse-shoe magnet is
laid in any position in reference to the experimenter, clock-rotation
is always obtained by holding the odometer half an inch above, and
beyond its northward pole; and versed rotation is invariably obtained
in like manner at its southward pole. The effect of touching the
odometer-finger with the thumb is exactly to reverse the two rotations.
I will now describe the individual instances in which these rotations
are manifested; or the parts of each Od-subject over which the odometer
rotates in opposite directions.