Lunes and biangles: quadrature figures, with a French address
Circle-portion geometry and arithmetic, plus a postal address to Leonardo, the King's painter, at Amboise
A large double-leaf covered with dozens of geometrical rosette, star and lune figures for the quadrature of the circle, worked in terms of 'biangles' and 'greatest portions' of a circle. Leonardo counts and equates areas (crossed-out figures worth the four greatest portions, lunes double one another, the least number of circle-portions being three, the triangle), interleaved with columns of arithmetic. Across the top runs a French postal address directing the delivery to 'M.r Lyonard florentin, paintre du Roy' at Amboise, a personal record from Leonardo's years in France.
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French address to Leonardo, painter to the King, at Amboise
A French address instructs the King's stable comptroller to have items delivered to Mr Leonardo the Florentine, painter to the King, for the affairs of the said lord, repeatedly naming Amboise. It records Leonardo's standing as painter to the King of France.
The least number of portions of a circle is three
The smallest number of portions that can be drawn from a circle is three, because the smallest rectilinear surface inscribed in a circle is the triangle, the next the square; the inscribed surface grows without limit as the number of its sides grows infinitely.
Lunes double one another
Two lunes are shown to be double one another, proved because the three circles involved are double one another. Companion figures repeat the relation of doubled lunes.
Halving series of nested circles
A group of circles nested one within another carries a descending halving series 64, 32, 16, 8, 4, 2 with labels a, c, b, expressing the proportional areas of the successive circles.
