Then there were two other results, which were directly at variance with my anticipations, but which never failed to present themselves. I made a voltaic arrangement by means of two plates, one of zinc, the other of copper, fixed in contact in a solution of salt in water. Now, when held opposite the middle of the zinc disc, the odometer always rotated like the hands of a watch; while over the copper disc the phenomenon was reversed. These results are constant. But I have had the satisfaction of lately discovering that, if I present the ring to any part of the _circumference_ of the two discs, its motion is the opposite, and in accordance with theory. One of the tests on which I have much relied in determining whether the motions I obtained were genuine Od-motions, consisted in producing their reversal by altering the Od-relations of my hand or of my person. What gives particular value to this test is, that the versed or complimentary motion is subject to different laws. One set of secondary oscillations changes into oscillations in a plane at right angles to the plane of the primary oscillations. In another series the motion continues in the same plane; but the excursions, which were before longest in one direction, are now longest in the opposite, as if a repellent current had been substituted for an attracting one. The Od-oscillations, it may be observed, are always dependent upon the action of a constant rectilinear force counteracted by the gravitation of the pendulum. The means I usually employ to reverse the primary Od-motions is, bringing the end of the right thumb into contact with the odometer-finger, where the thread is wound round it. But the experimenter cannot be too careful not to bring the thumb even near to the odometer finger, or to allow his other fingers to close upon the ball of the thumb, for the phenomena are thus again liable to be reversed. The other means of reversing the results of the experiments are:— _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. * * * * *