When two or three steps have been made upon the exciting tract of ground, the fork, which at starting is held horizontally, with the point forwards, begins gently to ascend; it gradually attains a vertical position; sometimes it passes beyond that, and lowering itself, with its point to the chest of the operator, it becomes again horizontal. If the motion continues, the rod descending becomes vertical, with the point downwards. Finally, the rod may again ascend and resume its first position. When the action is very lively, the rod immediately commences a second revolution; and so it goes on, as long as the operator continues to walk over the exciting surface of ground.
A few of those in whose hands the divining fork moves exhibit a remarkable peculiarity. The instrument, instead of commencing its motion by ascending, descends; the point then becomes directed vertically downwards; afterwards it reascends, and completes a revolution in a course the opposite of the usual one; and as often and as long as its motion is excited, it pursues this abnormal course.
Of the numerous experiments made by M. de Tristan, the following are among the simplest and the best:—
He covered both handles of a divining rod with a thick silk stuff. The result of using the instrument so prepared was the same which Mr. Fairholm obtained by coating the handles with sealing-wax. The motion of the divining rod was extinguished.
He covered both handles with one layer of a thin silk. He then found that the motion of the divining rod took place, but it was less lively and vigorous than ordinary.
By covering one handle of the divining rod, and that the right, with a layer of thin silk, a very singular and instructive result was obtained. The motion of the instrument was now reversed. It commenced by descending.
After covering the point of the divining rod with a thick layer of silk stuff, the motion was sensibly more brisk than it had been before.
When the Count held in his hands a straight rod of the same substance conjointly with the ordinary divining rod, no movement of the latter whatsoever ensued.
Finally, the Count discovered that he could cause the divining rod to move when he walked over a non-exciting surface—as, for instance, in his own chamber—by various processes. Of these the most interesting consisted in touching the point of the instrument with either pole of a magnetic needle. The instrument shortly began to move, ascending or descending, according as the northward or southward pole of the needle had been applied to it.
It is unnecessary to add that these, and all M. de Tristan’s experiments, were repeated by him many times. The results of those which I have narrated were constant.