Four Balanced Rods: Center of Gravity Always at Line m n
Four diagrams demonstrating that any proportion of the numbers returns the same result
Four diagrams of a cord-hung rod carrying numbered square weights fill the upper part of the leaf. Leonardo notes that whatever proportions one forms from the numbers shown, the line m n remains the center of all the weights. He invites the reader to begin with the arrangement '2 and 1 against 4' and to try the others below, since the rule is sound and always yields one and the same thing.
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The balance point m n holds for every arrangement
Across four suspended-rod figures Leonardo asserts that the line m n is always the center of all the weights. However the loads are distributed along the rod, the point of balance on its cords stays the same.
Any proportion of the numbers yields one conclusion
The opening line states that all the various proportions of the numbers present, however combined, return one same conclusion. The reader is told to try 2 and 1 against 4 first, then the further sequences (7 - 5 2 - 3 2, 7 - 6 1 - 4 2 1, and so on) shown below.