The Idealoscope: A clapable viewer for paper stereo views and glas stereo views in the size of 4,5 cm x 10,7 cm. The text of the description:
"Instructions for use of the Idealoscope Apparatus.
In order to make the apparatus ready for use, the elastically positioned front wall (bearing the lens) is so far opened that the dividing wall lying below can be easily turned into a vertical position by means of the handle. The fornt wall is then allowed to press against the dividing wall by which the small projection on the dividing wall fits into the slot of the front wall.
When glass pictures (4,5x10,7ctm) are to be seen through the apparatus, the frame is placed on the picture holder in the same manner as the paper pictures, and the glass picture is placed on the frame.
The apparatus is focussed to suit the eye by bushing the picture holder backwards and forward; this is done till the two pictures unite in a whole representing a natural perspective.
To close the apparatus again the front wall is first so returend to ist original position that the dividing wall can be conveniently laid over to the right.
Stereoscopic views 4,5x10,7cts. Fit for the Idealoscope .In finest high lustre workmanship. Per series of 26 pieces Mk. 1,60. "
