Postulates on rods and balances of equal arms
The centre of gravity of a rod; two- and three-armed balances; three weights in equilibrium
A "postulate" (Pitizione) defines a rod (aste) as a long body of uniform thickness and weight whose centre of gravity always lies at the middle of its length whatever its inclination, and states that a balance of two equal arms always returns to the level, while one of three equal arms enclosing three equal obtuse angles rests wherever it is turned. A second block, keyed to six lettered diagrams, works out how three weights arrange themselves about the pole of a triangular balance according to whether the middle weight is more or less than double the smaller. The recto is faint, with a small untranscribed sketch and further faint diagrams on the otherwise near-blank sheet.
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Postulate: the rod and balances of equal arms
A rod (aste) is defined as a long body of uniform thickness and gravity, with its centre of gravity always at the middle of its length and thickness whatever its obliquity. A balance of two equal arms always returns to the level, and one of three equal arms enclosing three equal obtuse angles will stop in any position it is turned to about its centre.
Three weights on a triangular balance
If the middle weight is less than double the smaller, the greater weight sits between the smaller and the pole; if it reaches or exceeds double, the smaller weight comes between the pole and the greater. The heaviest and lightest together counterbalance the middling weight, and their placement about the pole is governed by these proportional thresholds.