Nevertheless I am not without certain misgivings. I suspect that the divining-ring will be found to manifest genuine Od-motions in the hands of as small a number as succeed with the divining-rod. And I fear that overhasty confidence in results only seemingly sound, may lead many astray into a wide field of self-deception.
POSTSCRIPT.
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.