(18) The treadwheel
, as invented by the engineer, Sir William Cubbit, consisted of twenty-four steps, fixed lengthwise, like the floats of a paddlewheel, to a wooden cylinder sixteen feet in circumference, the steps being eight inches apart.
Control of body height in a stick insect walking on a treadwheel
Even with changes in the propelling mechanisms, from the horse whim, through the treadwheel
, and eventually to the portable treadmill, these animal ferries plied the open waters that were dangerous for smaller craft.
They were forbidden to speak under the silent rule, and if sentenced to hard labour, they endured long periods on the treadwheel
or at the crank.