Falling Water, Heavy Bodies, and the Balance's Angles
The descent of weights to the centre of the world, equilibrium of the balance, and a trick for foreshortened letters.
The left leaf opens with water cascading from the crest of a wave and rebounding as foam, then broadens into laws of descent: no heavy body moves unless it falls, its path runs toward the centre of the world, and nature always acts by the briefest way. The facing leaf, headed 'Mechanical elements', analyses the balance, showing that equal weights keep their hangers equidistant from the centre and enclose equal angles, while unequal weights tilt the beam. Diagrams lettered a, b, c, d and n, m accompany the reasoning about rest and equilibrium. A closing note explains how to cast foreshortened letters by passing sunlight through cut-out shapes onto stretched paper.
On this page
Water falling from the summit of a wave to its base
Water falls by whatever line from the summit of the wave to its base; its fall is swifter the less oblique it is, and slower the more oblique. The rebounding foam breaks up the more where it meets a more resistant object.
Heavy bodies descend to the centre by the shortest way
No heavy body moves of itself unless it descends, its motion running toward the centre and swifter with greater weight. Nature brings forth its effects by the briefest ways possible, and nothing is lower than the centre of the world, where the body comes to rest.
Equal weights make equal angles at the hangers
Under the heading 'Mechanical elements', weights that mutually resist in the balance keep the fastenings of their hangers equidistant from the centre of the world. When the weights resist equally, the angles formed by the junction of the hangers are equal.
The power of a suspended weight is entire along its cord
The power of every suspended weight is entire throughout all parts of the balance, and entire at every point of its hanger's length. At each degree of height the whole cord below is sustained together with the weight attached to it.
Rest where the central line cuts the motion at right angles
The moving body comes to rest where the central line of the world cuts the line of motion at two right angles, and upon an incline where its central line regards the centre of the world, cutting the line of its motion at two right angles.
Foreshortened letters cast by solar rays
To make foreshortened letters, stretch paper on a frame and draw, then cut out the letters and let the solar rays pass through those apertures onto another stretched paper; afterwards remake the missing angles.