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.
| CLOCK-ROTATION. | VERSED-ROTATION. | |
|---|---|---|
| a. A stick of sealing-wax excited by friction with flannel or silk. A glass tube excited by rubbing it with fur. | A glass tube similarly excited. | |
| b. The zinc disc of an arrangement of two zinc and copper discs moistened with salt and water, the odometer being held opposite to the middle of the zinc disc; for if it be held beyond the disc, half an inch from and on the exact level of the zinc disc, versed-rotation is manifested round the whole circumference. | The copper disc of the same, the odometer being held over against the surface of the copper disc; for again, if it be held to the edge of the copper disc, the opposite result follows, and the rotation is clock-rotation. | |
| c. A mixture of half a drachm of bicarbonate of soda and five grains of tartaric acid, when effervescing upon a plate after the addition of water. | A mixture of half a drachm of tartaric acid and five grains of bicarbonate of soda. | |
| d. The northward pole of a horse-shoe magnet, or of a magnetic needle freely suspended. | The southward pole of the same. | |
| e. One pole of a large crystal, which, is to be found out by this experiment. | The opposite pole. | |
| f. The root of a garden weed freshly taken from the ground. | The leaves of the same. | |
| g. The stalk end of an orange, and of an apple, and of an orange pip. | The opposite points of the same. | |
| h. The small end of an egg. | The large end of the same. | |
| i. The tips of the fingers on either hand, and of the toes of either foot. | The top of the thumb and great toe. | |
| k. Right side of the head of a sparrow. | Left side. |
The last holds likewise with the greater part of the human body; but the results of trying the odometer with the human frame are so complicated, that I shall reserve their consideration for a separate section.
V. The mechanical solution of these phenomena is simple enough. The odometer must be under the influence of two constant and unequal rectilinear forces, operating at right angles to each other on the gold ring, the effects of which are modified by the centripetal force of its gravitation. All that is required is, to determine by observation the place, direction, and limits of the two forces.
It will render the description which follows easier, to suppose that the pole of the Od-subject which causes clock-rotation be turned directly from the experimenter; for example, that an egg be placed longways to the experimenter with its small end from him, or a bar magnet with its northward pole from him. In the case of a horse-shoe magnet, both poles are then turned from you. So, too, in the case of the hand, the fingers and thumbs are both to be turned away.
a. Odometer held immediately before, and a quarter of an inch from, the small end of an egg. Result—Distad motion, or motion in the direction of the long axis of the egg, from the egg.