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1856] ad sin (ad) + be sin (be) + cd sin (cd)]. Hence, except in the case of a rectangle the formula gives a result which is too large. Peet (1923, 2) is therefore in error when he argues (p. 94) that the tenant "never lost by this rough system of measurement" in paying taxes according to the extent of his ﬁeld. "This method of measuring was admittedly no more than an approximation for taxation purpose, and fractions less than $1/undefined$ of a square Khet, sometimes even$1/undefined$ of a square Khet, were omitted" (Peet); compare H. Maspero, Les finnances de l'Égypte sous les Lagides, Paris, 1905, p. 135.

An important supplement to the memoir of Lepsius is H. K. Brugsch ''Thesaurus I nscriptionum Aegyptiacarum. Astronomische und astralogische Inschriften, altaegyptischer Denkmaeler'', 3. Abteilung, Geographische Inschriften Leipzig, I884, pp. 53l—618. For two other references to sources using the above method for computing quadrilateral areas, between 100 B. C. and about 550 A. D., see ''Greek Papyri in the British Museum. Catalogue, with Texts, edited by F. G. Kenyon, London, vol. 2, 1898, pp. 129-141; B. P. Grenfell, A. S. Hunt, J. G. Smyly, The Tebtunis Papyri, London, part I, I902, pp. 385-393; and H. R. Hall, Coptic and Greek Texts of the Christian Period from Ostraka in the British Museum'', London, 1905, p. 128, ostracon 29750, and plate 88. Compare Peet (1923, 2) pp. 93-95. A reference may also be given to: H. Weissenborn, “Das Trapez bei Euklid, Heron und Brahmagupta," Abhandlungen zur Geschichte der Mathematik. Leipzig, Heft 2, 1879. especially