The Egyptian Book of the dead by P. Le Page Renouf and Edouard Naville

_stretching_, which is the conception implied in this name of the instrument. This mythological _Bow_, as I explained, _Proc. Soc. Bibl. Arch._, VI, 131, is the moon’s _crescent_, which during its course through the sky is always turned towards the sun; so that a line at right angles to the chord of the arc passes through the sun’s centre. From this “very delicate observation,” as Arago calls it, the Alexandrian astronomer Geminus infers that the moon derives its light from the sun. The observation evidently had been made in Egypt some thousands of years before Geminus, and explains why in several chapters the sun is spoken of as shining in or from the moon. See also _Proc. Soc. Bibl. Arch._, XVII, 37, on another form of the myth.