PLATE IV.
(x) The apparatus of which the opposite cuts afford a representation are spiritoscopes, under modifications to which I resorted subsequently to the contrivance in which Pease’s dial is employed. For Pease’s “dial,” disks are substituted, resembling those originally employed by me, as represented in Plates I. and II. These last mentioned, however, were made to revolve under the index; while in Pease’s apparatus the index revolves, the disk remaining at rest. The advantage of having the disk to revolve is, that the letter is always to be looked for, within the same space; whereas in operating with the other the eye has to follow the index through all its rapid movements.
(y) The convenience and economy of casting the disks of iron was deemed a sufficient motive for resorting to the rotation of the index; as when made of that metal the disk becomes too heavy to be rotated with ease, first one way and then another.
(z) In Fig. 1 the vibrating lever is resorted to, and the process is precisely the same as that already described, in which Pease’s dial is associated with the same mechanism.
(aa) The words on the dial faces in Figures 1 and 2 are somewhat abbreviated.[2]
(bb) The rod R slides in staples, so as to be made to extend farther or nearer from the fulcrum. The legs on which the disk is supported, which are a part of the casing, terminate below in a socket which fits upon a plug screwed into the base-board; upon this plug it may be fastened by the set screw (s). By sliding the rod (r) inward, the disk may be turned half round upon the plug, so as to place the lettered surface out of the sight of the medium, whose power to influence the communications is thus nullified. This is one mode of attaining test conditions; in other words, those conditions which make it impossible that the communications received should be due to any mortal, (151 to 166,) unless, as gratuitously and erroneously, as I believe, alleged, the medium by clairvoyancy sees the letters.
(cc) By another method test conditions are obtained which are not exposed to this evil.
(dd) The method to which I allude has been explained in the description of Plate I. in reference to the spiritoscope formed with the aid of a Pease’s disk, paragraph (e). The process is the same in the employment of Fig. 1 Plate IV. under consideration. It may be better understood in this case, as the illustration of the lever board L is more conspicuous. In the ordinary mode of operating without test conditions, the hand of the medium is so situated as to have nearly half of it beyond the fulcrum, marked by the line F L. When test conditions are imposed, the tips of the fingers only reach to that line, without going beyond it. Situated as last mentioned, the medium to whom they appertain cannot move the rod R, because it is already against the lower edge of the disk, which prevents it from moving upwards. In the opposite direction the medium can create no pressure, since her efforts could only tend to lift her hand, per se, from the disk. It is important that the reader should pay attention to this exposition, as the conditions thus made evident are often appealed to as one proof, among others, that my information and credentials are from the immortal worthies of the spirit world.
(ee) Fig. 2 is analogous in its mode of operating, to the apparatus represented in Plate II. It is in the substitution of a small board for a table that the principal difference consists.[3] The board requires only to be large enough to allow the hands to rest upon it in front of the disk. The index is actuated by a horizontal motion to and fro, which, as in the apparatus, Plate II., causes the rotation of a supporting wheel, which by means of a band communicates rotation to a pulley supported behind the disk on the pivot to which the index is secured in front. The sliding pulley P being fastened at a due distance from the disk (o), is used to keep the band tight.
(ff) This instrument is preferred by the spirits, and is easier for a feeble medium to employ effectually. I cannot as yet avail myself of Fig. 1; through Fig. 2 I have had some interesting tests.