831. In striving to make a test apparatus by which the communication should be uninfluenced by the muscular power of the medium, through which alone her will could modify the ideas communicated, an interesting fact was ascertained. The nullifying of the power of muscular control, which it is the object of this contrivance to accomplish, is obtained unexceptionally by means of two balls and a plate, as already illustrated, (Plate 2,) or by placing the hands of the medium exterior to the fulcrum of the lever-board, as described in the instance of testing the communication received from the convocation. But these methods requiring that the conditions should be favourable, both, as respects the spirit communicating and the medium, are liable to fail. It struck me that the distance between the hands and the surface of the table or tray to be moved, by lessening the influence of the medium on the table or tray, lessened the power of actuation. My efforts were therefore directed to contrive to have the hand of the medium near the surface to be moved, without the possibility of contact. 832. With this view I placed a board for receiving the hands of the medium upon delicate rollers, so that no horizontal movement would affect the base board supporting the rollers and actuating the index. To give greater efficacy to the aura, a plate of glass was supported in a wooden frame or sash by means of four screw rods fixed upright on the base board, each furnished with two screw nuts. The screw rods passed through four suitable holes, so as to have one nut beneath, the other above, the sash. Thus situated, by adjusting the nuts, the sash could be regulated to any horizontal level, so as to be near the upper surfaces of the hands without any contact therewith. 833. On trying this arrangement, it was found as difficult for a spirit to actuate it as if the glazed sash had not been employed. 834. Under these circumstances, I had the glass plate or pane slit lengthwise into two equal strips. These being restored to the position previously occupied in the sash, I interposed between their edges a piece of sheet-tin, with teeth cut in one of its edges, (Plate 4, _kk_,) so as to make it look like a long narrow saw, such as are used by sawyers in frames. With the aid of a leaden joint, (such as is used by glaziers to join glass panes,) to which the saw was soldered, the teeth of this projected about the eighth of an inch below the glass, so as to be near the upper surface of any hand, resting on the sliding board. 835. It was with no small degree of satisfaction that I found the apparatus now sufficiently susceptible of actuation by my spirit friends. 836. From this result it would seem that the saw-shaped metallic conductor, operated precisely as it would have acted had it been necessary to impart to the pane those means of electric discharge of which, as at first used, it was deficient.