Peg wheel and worm screw; friction of the lantern pinion
With a houseleek-among-flames device and its motto
The upper page is dominated by a peg wheel — a circle rimmed with dots for its pins — mounted on a vertical shaft marked L that engages a worm screw. Below and to the centre a plant sprig is drawn among flame-like strokes, with a short motto beneath it that this bundle does not transcribe. The supplied text analyses the friction between a wheel's tooth and a lantern-pinion's spindle: the nearer the pinion sits to the wheel's diameter, the less it rubs, and a screw-type pinion, though easily driven by the wheel, can scarcely drive the wheel in return.
On this page
Peg wheel on a shaft (L) driven by a worm screw
A wheel studded with pins around its rim turns on a vertical shaft labelled L, meshing with an endless (worm) screw. The drawing illustrates the gear pairing that the friction notes discuss.
Friction least when the pinion sits near the wheel's diameter
The closer the lantern-pinion is placed to the wheel's diameter, the less the friction the wheel's tooth makes along the length of the pinion's spindle; the farther out the pinion is set, the greater that rubbing becomes.
A screw pinion easy to drive but poor at driving
The simple straight turn of the screw is best turned by the wheel when set farthest from the diameter, more than any other kind of pinion. Yet such a pinion can never move the wheel with the ease with which the wheel moves it.
Device of a houseleek among flames
At the centre a plant sprig rises through flame-like strokes, forming an impresa. A short motto is inked beneath it; it is not part of this entry's transcription and is noted here only as visual evidence.