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A history of Greek mathematics - Wilbourhall.org

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comparatively<br />

MENSURATION 317<br />

does not use concrete measures, but simple numbers or units<br />

which may then in particular cases be taken to be feet, cubits,<br />

or any other unit <strong>of</strong> measurement. Up to 1896, when a<br />

manuscript <strong>of</strong> it was discovered by R. Schone at Constantinople,<br />

it was only known by an allusion to it in Eutocius<br />

(on Archimedes's Measurement <strong>of</strong> a Circle), who states that<br />

the way to obtain an approximation to the square root <strong>of</strong><br />

a non-square number is shown by Heron in his Metrica, as<br />

well as by Pappus, Theon, and others who had commented on<br />

the Syntaxis <strong>of</strong> Ptolemy. 1 Tannery 2 had already in 1894<br />

discovered a fragment <strong>of</strong> Heron's Metrica giving the particular<br />

rule in a Paris manuscript <strong>of</strong> the thirteenth century containing<br />

Prolegomena to the Syntaxis compiled presumably from<br />

the commentaries <strong>of</strong> Pappus and Theon. Another interesting<br />

difference between the Metrica and the other works is that in<br />

the former the <strong>Greek</strong> way <strong>of</strong> writing fractions (which is our<br />

method) largely preponderates, the Egyptian form (which<br />

expresses a fraction as the sum <strong>of</strong><br />

being used .<br />

case in the other works.<br />

diminishing submultiples)<br />

rarely, whereas the reverse is the<br />

In view <strong>of</strong> the greater authority <strong>of</strong> the Metrica, we shall<br />

take it<br />

as the basis <strong>of</strong> our account <strong>of</strong> the mensuration, while<br />

keeping the other works in view. It is desirable at the<br />

outset to compare broadly the contents <strong>of</strong><br />

the various collections.<br />

Book I <strong>of</strong> the Metrica contains the mensuration <strong>of</strong><br />

squares, rectangles and triangles (chaps. 1-9), parallel-trapezia,<br />

rhombi, rhomboids and quadrilaterals with one angle right<br />

(10-16), regular polygons from the equilateral triangle to the<br />

regular dodecagon (17-25), a ring between two concentric<br />

circles (26), segments <strong>of</strong> circles (27-33), an ellipse (34), a parabolic<br />

segment (35), the surfaces <strong>of</strong> a cylinder (36), an isosceles<br />

cone (37), a sphere (38) and a segment <strong>of</strong> a sphere (39).<br />

Book II gives the mensuration <strong>of</strong> certain solids, the solid<br />

content <strong>of</strong> a cone (chap. 1), a cylinder (2), rectilinear solid<br />

figures, a parallelepiped, a prism, a pyramid and a frustum,<br />

&c. (3-8), a frustum <strong>of</strong> a cone (9, 10), a sphere and a segment<br />

<strong>of</strong> a sphere (11, 12), a spire or tore (13), the section <strong>of</strong> a<br />

cylinder measured in Archimedes's Method (14), and the solid<br />

1<br />

2<br />

Archimedes, vol. iii, p. 232. 13-17.<br />

Tannery, Memoires scientifiques, ii, 1912, pp. 447-54.

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