Domestic Encyclopædia (1802)/Supplement/Exercise
![](http://upload.wikimedia.org/wikipedia/commons/thumb/f/f4/Domestic_Encyclopedia_1802_vol4_p460.jpg/250px-Domestic_Encyclopedia_1802_vol4_p460.jpg)
The engine consists of a wooden cylinder, a, which turns on two central pivots, e, e, inserted in the upright posts.—b, b, are two rods, that may be made either of iron or of strong wood. These bars intersect each other at right angles, and are furnished with leaden weights at their extremities, c, c, c; which turn the cylinder with great velocity, when the rope d, attached to and passing round it, is pulled downwards. Farther, such weights draw the rope up again with considerable force, while it is wound backwards and forwards over the cylinder.—As this machinery may be fixed in a garret, or other spare-room at the top of a house, the rope may be conduced through the ceiling into a lower chamber; so that sedentary persons, or invalids, may take sufficient exercise, without quitting their habitation, or exposing themselves to the vicissitudes of the weather.