Colour drawings of a rainbow at sea and on land, from the sketchbook of Jan Brandes, Vol. 1 (1808).
Featured on PDR in the collection Rainbows in Art
Or, since that hope denied in worlds of strife,
Be thou the rainbow in the storms of life!
The evening beam that smiles the clouds away,
and tints tomorrow with prophetic ray!
(Lord Byron, The Bride of Abydos)