Balancing Two Tackle-Hung Weights at m and n
A tested rule: multiply by the number of sheaves to make the loads equal
Two block-and-tackle hoists are drawn at the top of the page, their weights labelled m and n, with the note that the scheme has been tried out. Leonardo gives the rule for equalizing them: to find the weight at n that balances the weight at m, multiply the weight put at n by the number of sheaves in the blocks, and the product is the pounds to hang at m. He marks the layout with the numbers 4, 1 and 4, 4 beside the labels m and n.
On this page
Rule to make the weight at n balance the weight at m
To learn what weight must be set at n so it stays even with the weight at m, multiply the weight you mean to put at n by the number of the tackle's sheaves. The resulting sum is the number of pounds you must hang at m, and the two will stand equal.
Two tackles compared, and marked 'tested'
Two hoists are set side by side, their loads labelled m and n and tagged with the figures 4 1 and 4 4. Leonardo writes that the arrangement has been tried out in practice.