Rules of perspective and motion; the magnet and beam flexure
Propositions on apparent size with distance, on bodies in motion, and on the bending of loaded rods.
The main leaf gathers short propositions headed alternately 'Perspective' and 'Motion'. Three perspective rules state how apparent height and size change with distance from the eye; three notes on motion argue that more distant motions seem slower, that bodies bound by a material tie cannot move one another without moving themselves, and that bodies joined by a 'spiritual tie' draw the lighter toward the heavier, as the lodestone does. A second block works out how a loaded rod bends, relating the deflection of one rod to that of several bound together. At the right a small detached scrap carries a drawn cylindrical device resembling a lantern or cage, which is not part of the transcription.
On this page
Three rules of perspective for height, depth and size
Of things of equal height set above the eye, the more distant appears lower; of things equally low set below the eye, the more distant appears higher; and of things of equal size, the one nearer the eye appears of greater form. The propositions treat the apparent shift of position and scale with distance.
Motion, material and 'spiritual' ties, and the lodestone
Among motions of equal quickness the more distant from the eye seems the slower. Bodies linked by a material bond cannot impart motion without themselves moving; but bodies joined by a 'spiritual' bond let the heavier draw the lighter to itself without moving, as the magnet does.
The flexure of a loaded rod
A rod of 10 braccia carrying 100 libbre sinks one braccio; four such rods bound together sink only half a braccio. The half-rod is as strong as eight whole ones bound together, and in every arch the rod passes lower than its proportion as its ends are drawn nearer by the curvature.
Small drawn cylindrical device
A separate narrow scrap at the right bears an ink drawing of a small cylindrical object with vertical staves, a loop or handle at the top and a base, resembling a lantern or cage. No transcription accompanies it.