The endorsed ship George Washington of the Blue Swallowtail Line had already sailed, so the New York post office instead sent this letter via the next available ship – Black X Line’s Montreal.
After the War of 1812-15, full-rigged American ships began to dominate the North Atlantic trade. Within only a few years mail could be sent weekly against a published schedule. The cost of mail was cheaper and the sailings more frequent the Falmouth Packets, which were soon discontinued as non-competitive. The sender of this letter paid 12 ½ cents inland postage to New York, and designated conveyance by the Blue Swallowtail ship George Washington. That ship had already sailed, so the letter went via the Black X Line’s Montreal, which departed on 10 October, and arrived at Portsmouth on 8 November. London rated the letter 2/4 due: 8d ship fee plus 8d inland postage to London.