Stool with top moving parallel to it's bottom.
The only known image of this mechanism was found in the book "How to draw a straight line. A lecture on linkages." by A. B. Kempe.
Museums and archives:
- Until 1933 mechanism was stored in the Science Museum (London, UK); № 1877-440.
- Document, stored in the Science Museum (London, UK).
- D. A. Grave. Encyclopedia of elementary mathematics. An essay on its contemporary state. — Kiev: Edition of N. Ya. Ogloblin’s book store, 1912. (Russian)