Suspended Geometric Figures for Centres of Gravity
Circle, square and rectangle hung by plumb-lines beside mirror-script notes
This left-hand leaf sets a column of plain geometric figures against blocks of Leonardo's mirror-script, none of which is transcribed in this bundle. Each figure, a circle, an upright rectangle, a square holding a smaller square set corner-to-corner, and a leaning parallelogram, is drawn with a vertical thread and a small weight hanging from it, as in a study of balance and centre of gravity. A circle with two crossed diameters and points marked with letters appears among them, and a faint offset circle shows through near the foot of the page. Further untranscribed writing surrounds the diagrams.
On this page
Geometric shapes suspended by weighted plumb-lines
Several figures, a circle, an upright rectangle, a square and a leaning parallelogram, each carry a vertical line ending in a small hanging weight. Suspending a shape from a point in this way lets the plumb-line pass through its centre of gravity, the classic method of locating balance. The drawings read as an investigation of equilibrium in simple plane figures.
Square inscribed with a smaller square set corner-to-corner
One figure shows a square containing a second, smaller square rotated forty-five degrees so that its corners touch the midpoints of the outer sides. A circle with two perpendicular diameters, its ends tagged with letters, sits higher in the same column. These are exact plane-geometry constructions used to reason about the figures' symmetry and centres.