Richard II. Act iii. Sc. 3.
The clearness of vision in birds is indeed extraordinary, and has been calculated, by the eminent French naturalist Lacépède, to be nine times more extensive than that of the farthest-sighted man. The opinion that the eagle possessed the power of gazing undazzled at the sun, is of great antiquity. Pliny relates that it exposes its brood to this test as soon as hatched, to prove if they be genuine or not. Chaucer refers to the belief in his “Assemblie of Foules”:—
“There mighten men the royal egal find,
That with his sharp look persith the sonne.”
So also Spenser, in his “Hymn of Heavenly Beauty,”—
“And like the native brood of eagle’s kind,
On that bright sun of glory fix their eyes.”
It is not surprising, therefore, that Shakespeare has borrowed the idea:—
AN EAGLE EYE.
“Nay, if thou be that princely eagle’s bird,