The Measurers:
a Flemish Image of Mathematics in the Sixteenth Century

Figure 19
The use of the geometrical quadrant.

From Adriaan Metius, ArithmeticŠ libri duo: et geometriŠ libri VI (Leiden, 1640).
The linear division of the sides of the square means that the angles required are taken as ratios instead of in degrees; this allows the convenient conversion of, for example, lengths measured on the ground to inaccessible heights.

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