This text comes from The Poetical Works of John Keats, a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
Son of the old moon-mountains African!
Stream of the Pyramid and Crocodile!
We call thee fruitful, and that very while
A desert fills our seeing's inward span:
Nurse of swart nations since the world began
Art thou so fruitful? or dost thou beguile
Those men to honor thee, who, worn with toil,
Rest them a space 'twixt Cairo and Decan?
O may dark fancies err! They surely do;
'Tis ignorance that makes a barren waste
Of all beyond itself. Thou dost bedew
Green rushes like our rivers, and dost taste
The pleasant sun-rise. Green isles hast thou too,
And to the sea as happily dost haste.