Making a triangular balance
A circle divided into three arms, and a twelve-sector weighing wheel
Leonardo sets out how to build a 'triangular balance' by dividing a circle into three equal parts and drawing a line from each division to the centre, giving a three-armed weighing figure. The upper drawings show the resulting three-spoke circle beside a Y-shaped balance carrying square weights on cords. Below, a wheel divided into twelve numbered sectors accompanies a note on adjusting the weights so that each side balances alike.
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Constructing the three-armed balance from a circle
To make the triangular balance, divide a circle into three equal parts and draw a straight line from each division to the centre. The resulting three-spoke figure defines the arms of the balance.
The twelve-sector weighing wheel
A circle is divided into twelve numbered sectors, 1 through 12. Leonardo asks what position the number 7 will settle into, and answers that one must set the wheel so its weights are equal on one side and alike on the other, and then observe.