The slider is rather smaller than the stage in the lantern, which allows of it being adjusted so that the centre of the picture is in a line with the centre of the lenses.
For making movable slides, such as slipping-slides, lever-slides, rack-slides, and chromatropes, you will require wooden frames.
To make these frames, get a carpenter to cut you some slips of pine or deal three or four feet long and half an inch square, with a groove running all along one side of each slip say one-eighth of an inch deep and one-sixteenth of an inch wide. Make your frames out of these slips of wood, seven inches long and four inches wide, outside measuring. Fit a glass in the groove like a slate is fitted in its frame.
Fig. 4
Fig. 5
Make about a dozen of these frames, and set them on one side to dry. Now cut some strips of glass three inches wide and seven inches long, and cut off one corner of each, as in [Fig. 4], at any convenient angle, and then cut away the upper half of the front part of each frame flush with the glass, to allow the second glass to be pulled out about half an inch when put in position in the frame, as in [Fig. 5].
