Supports, balance arms, and four pulls of a ball
Angles versus bases; the support loaded nearest the weight's centre
Leonardo voices a doubt over whether the load should be reckoned by the proportion of the angles or of the bases, remarking on the great difference between the two. He then states that the part of a lower support nearest the centre of its weight bears the most, and closes by asking which of four 'pulls' will, in one complete turn, raise its ball highest. Bracket, balance-beam and sling diagrams with a spiral pulley accompany the notes.
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Angles or bases?
A doubt arises whether to hold to the proportion of the angles or of the bases in reckoning how a support is loaded, because there is a great difference between the two measures. The choice of rule changes the calculated distribution of the weight.
The support loaded nearest the weight's centre
That part of the thickness of the lower support is the most burdened which lies closest to the centre of the weight it sustains. The load concentrates on the material directly beneath the weight's centre of gravity.
Which of four pulls raises the ball highest
Leonardo asks which of four pulls, in one complete turn, will raise its ball highest, and by how much. The question compares the mechanical advantage of four different lifting arrangements.