The jack is a machine, today quite well-known in the car jack version, it is used to raise heavy objects to limited heights.
The model presented is mounted on a wooden frame composed of a shaft 9.5 cm wide and 30 cm long, painted red and held by a rectangular base plate 18.5 cm wide and 9.5 thick, painted black.
The actual machine, made all of iron, is composed of a sturdy vertical shaft 3.5 cm wide and 35 cm long, which runs on the frame in a guide; it raises by about 19 cm a horizontal shaft welded at the lower extremity, with respect to which it protrudes 22.3 cm.
The raising takes place by hand by means of a crank that turns a gear wheel; this in turn acts on the shaft by means of another reducing gear.

Turner (1983), p. 80

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