E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Mulready Envelope (The, 1840),
is an envelope resembling a half-sheet of letter-paper, when folded. The space left for the address formed the centre of an ornamental design by Mulready, the artist. When the penny postage envelopes were first introduced, these were the stamped envelopes of the day, which, however, remained in circulation only one year, and were more fit for a comic annual than anything else.
A set of those odd-looking envelope-things,
Where Britannia (who seems to be crucified flings
To her right and her left, funny people with wings
Amongst elephants, Quakers, and Catabaw kings,
And a taper and wax, and small Queens-heads in packs,
Which, when notes are too big you must stick on their backs.