| 摘要 |
A pair of closed loop tracks provides a stationary slideway for slide (transparency) holders which are hinged together sequentially in an endless loop arrangement. A particular slide is selected for viewing by advancing the holders in the slideway to a viewing position at which the selected slide is reoriented from a normally radial to a peripheral orientation. Illumination from a source at the axis of the slideway permits viewing without extraction of the slide from the track.
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