Friction on a Loaded Cord and a 'Sophistic Motion' Device
Sliding-friction equilibrium of weights over a pulley, with a mock perpetual-motion machine
The sheet studies friction (confregatione): a cord t a c that tends to straighten along t a b, and a weight n f that will not move unless f is lifted from the ground, so that the ratio of lines r n and n M gives the ratio of the weight n f to the weight X plus the added resistance of friction. A short 'Definition' treats point n as the pole of a balance whose arms are r n and n M, weighing 8 pounds against 16, and reasons that a friction-power of one would let 17 stand equal against 8. At the upper left a circular device is inscribed with the number 100 repeated six times, beside a note on a 'sophistic motion' made with wine and pressed grapes and kept going by the timing of clocks. Further untranscribed writing is faintly visible in the lower half of the sheet.
On this page
A cord that seeks to straighten and the friction of its load
The cord t a c wants to straighten along t a b, and the weight n f will not move unless f rises from the ground. The ratio of line r n to line n M equals that of weight n f to weight X plus the extra due to friction, in which every degree of motion produces degrees of weight. A definition makes n the pole of a balance with arms r n and n M, hanging 8 pounds against 16.
A 'sophistic motion' kept going by clockwork
A note describes a 'sophistic motion' made with wine and pressed grapes, said to begin at the place shown and to sustain its movement by the time of clocks. It sits beneath a circular device whose interior is marked with the number 100 repeated six times.