An accident has given me the opportunity of making further additions to
this little volume, of which I proceed to avail myself; and, first, by
communicating my latest experiments with the divining-ring, July 24.
I. I have stated that, if a fresh egg be placed upon the table, with
the small end directed _from_ me—or a crystal, with one definite
pole so turned from me—or a bar-magnet, with its northward pole so
disposed—and I then suspend the divining-ring half an inch above either
of the three so averted ends, and half an inch further off from me,
the ring exhibits clock-rotation in each instance. Held in a parallel
manner over the opposite ends—that is, half an inch from, and half an
inch higher than, the same—the ring exhibits versed-rotation. If the
three Od-subjects be moved round, so that their hitherto distal ends
point to the right, or if they be further turned, so as to bring the
previously distal ends now to point directly _towards_ me, the ring
continues to exhibit exactly the same motions as in the first instance.
If, these objects being removed, I lay a horse-shoe magnet on the table
before me, with its poles turned directly _from_ me, the northward
limb being on my left hand, the southward limb-pole on my right, and
experiments parallel to those just described are made, the results
remain the same. If, near one side of the horse-shoe magnet, I lay my
left hand on the table, the palm downwards, the thumb held wide of the
fingers, the ring, if suspended half an inch from and above either of
the finger-points, displays clock-rotation; suspended similarly before
and above the point of the thumb, versed-rotation. Or the fingers of
the left hand, so disposed, may be compared, in reference to Od, to the
northward pole of a horse-shoe magnet, while the thumb corresponds with
its southward pole.
If, removing my left hand, I turn the horse-shoe magnet, without
altering the side on which it rests, half round, so that the poles
point directly _towards_ me, the northward pole being now, of course,
on my right, the southward pole on my left, the ring held as before
over either of the two poles, displays the same results. If I now
move the magnet still nearer to me, so that its two poles are an inch
beyond the edge of the table, I can obtain results which furnish a more
precise explanation of the two rotatory movements already described,
than I had before arrived at.
If I now suspend the ring, with its lowest part on a level with the
magnet, and half an inch from its northward pole—that is, half an
inch nearer me—it begins to oscillate longitudinally, with a bias
towards me, as if it were repelled from the pole of the magnet. If
I then suspend the ring an inch vertically above the first point of
suspension, it begins to oscillate transversely, with a bias towards
the right, or as if impelled by a dextrad current. If I then lower the
ring half an inch, the first effect observed is, that it oscillates
obliquely, being evidently impelled at once to the right and towards
me—that is, in the diagonal of the two forces, of each of which I had
before obtained the separate influence. In this third variation of the
experiments, I have brought the ring to the limit of the two currents,
where both tell upon it. This oblique oscillation soon, however,
undergoes a change: it changes into clock-rotation, showing that the
transverse or dextrad current is stronger than the longitudinal or
proximad current.
If parallel experiments be made at levels below that of the pole of the
magnet, corresponding but opposite results ensue. If the whole series
be repeated upon the south pole of the magnet, opposite but perfectly
corresponding results are again obtained: and similar results may be
obtained with the two poles of an egg.
II. The mode in which I have latterly educed the rotatory movements
depending upon galvanism, has been this. I have laid two discs, one
of zinc, the other of copper, one on the other, having previously
moistened their surfaces with salt and water. Then, as I mentioned,
the ring held over the middle of the zinc disc (that being uppermost)
exhibits clock-rotation. Held over the middle of the copper disc, when
that is laid uppermost, versed-rotation. I mentioned, too, that if held
beyond, but near the circumference of the same discs, the direction of
the motion of the ring is reversed.
The discs which I employ are circular, an inch and a half in diameter,
and about as thick as a sovereign. Upon these I do not fail to obtain,
when dried and used singly, the first series of phenomena described in
the preceding letter. But it occurred to me to try what would be the
result of suspending the ring over the two together, and alternately
laid uppermost, when they had been well cleaned and dried. This is
evidently a still simpler voltaic arrangement than when the salt and
water is additionally used. The result was in the highest degree
interesting. When I suspend the ring half an inch above the centre
of the copper disc, (that being laid uppermost,) the first motion
observed is transverse; but after a few oscillations it becomes
oblique—dextrad and proximad combined, in the diagonal between the
primary influences of the zinc and of the copper. This change does not
last long; the transverse force again carries it, in this instance, and
clock-rotation is permanently established. When the zinc is uppermost,
the corresponding opposite phenomena manifest themselves; and in either
case a reversed movement occurs, if the ring is held extra-marginally
to the discs.
III. I may say that I have now obtained positive evidence that these
motions of the odometer do not depend upon my own will, or the sympathy
of my will with existing conceptions in my mind; for they succeed
nearly equally well when the discs are covered with half a sheet of
writing-paper. In nine cases out of ten, when I thus manage to be
in perfect ignorance which disc, or what combination of the two, is
submitted to the odometer, the right results manifest themselves, and
the cause of the occasional failures is generally obvious. Let me add
upon this topic, that one day, the weather being cold and wet, and
myself suffering severely with rheumatism, the odometer would not move
at all in my hand. On another day, late in the evening it was, when I
happened to be much fatigued and exhausted, the ring moved, indeed,
but every motion was exactly reversed; thus my left hand I found now
obtained exactly the results which, on other occasions, I got with the
right.
* * * * *
IV. But by what cause, then—through what mechanism, so to speak, are
the movements of the odometer immediately produced? Early in the
inquiry I made this experiment. Instead of winding the free end of the
silk round my finger, I wound it round a cedar-pencil, and laid the
latter upon the backs of two books, which were made to stand on their
edges, four inches apart, with the Od-subject on the table between
them, the ring being suspended half an inch above it. The ring, of
course, remained stationary. Then I took hold of the pencil with my
finger and thumb, at the point where the silk was wound round it; my
finger and thumb rested on the silk; but no motion of the odometer
ensued. Hence it follows, that the odometer is, after all, always set
in motion _by the play of my own muscles_. I venture then to suppose
that my sentient nerves, unknown to me, detect on these occasions
certain relations of matter—let me call them currents of force—which
determine in me _reflexly_ certain sympathetic motions of the very
lightest, and even of an unconscious character. This idea, which I am
sure affords the just solution of the matter, is highly consistent
with some observations which I have before recounted. It explains how
the primary delicate impression should yield to the coarser influence
of a strong conception in the mind, that this or that other motion
of the ring is about to follow, or even to that of a vivid and, so
to say, abstract conception of another motion. It explains what I
have several times verified, that on certain days a person standing
behind me with his hand on my ear, or on my shoulder, can, by an
effort of his will (mine not resisting,) make the odometer which I am
holding move whichever way he happens strongly to image to himself,
without communicating the same to me. It explains to me on what the
difference consists between those who can set the divining-ring in
motion, without a conscious effort, and those who cannot. The former,
it will be found, are persons of so great nervous mobility, that any
such motions, if their occurrence be forcibly anticipated by them, will
certainly be realized by their sympathetic frames. Among this class
should be sought, and would still remain to be detected by experiment,
those whose _impressionability by Od should prove commensurate with
their nervous mobility_. Finally, I cannot doubt that the view which
I have thus arrived at respecting the mechanism of the motions of the
odometer, is equally applicable to the explanation of those of the
divining-rod. I see that, through its means, many before anomalous
facts, with the narrative of which I have not bored the reader, which
emerged in my former trials of the divining rod, made by the hands of
others, lose their obscurity and contradictoriness, and leave the whole
subject in the condition of an intelligible and luminous conception.
N. B.—It is a pity that of the inquirers who now amuse themselves with
investigating these subjects, very few realize in their minds the idea
of Von Reichenbach, that Od, though often exhibiting the same relations
with electricity and magnetism, is yet an utterly different principle.