(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 crucifiedt flings To her right and her left, funny people with wings Amongst elephants, Quakers, and Catabaw kings,- And a taper and wax, and small Queen's-heads in packs, Which, when notes are too big you must stick on their backs.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894