The three centres of a tapering rod (pyramid)
Sesquitertian (4:3) proportion and the centres of natural and accidental gravity
Two figures of a composite, tapering rod are labelled with the sesquitertian proportion (4:3). The accompanying note states that such a 'pyramid' has three middles: the middle of its natural gravity, that of its accidental gravity, and that of its length. The middle of the natural gravity falls between the third and quarter of its length, and the middle of the accidental gravity at the third of its length. Small geometric figures with fractions and a circle-and-square series appear elsewhere on the faint sheet.
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Three centres of a tapering rod
The pyramid (tapering rod) has three middles: the middle of its natural gravity, the middle of its accidental gravity, and the middle of its length. The middle of the natural gravity lies between the third and the quarter of its length, while the middle of the accidental gravity lies at the third of its length.
Sesquitertian (4:3) proportion
The composite rod is labelled with the sesquitertian proportion, the ratio 4:3, which governs the division of its length in the accompanying analysis of gravity centres.