black datestamp with matching boxed "30" handstamp on 1854 folded letter to William George Stewart in New York City, indicating triple the 10c unpaid cross-country rate, very fine, the latest known use of this handstamp, ex-Jessup

This cover is accompanied by an article written by Harry M. Konwiser in Stamps magazine (1941) illustrating and describing the unusual use of this handstamp at such a late date. Typically the boxed "30" of San Francisco was used on incoming steamship mail through 1851 to pay the Panama rate to California. Additionally the article describes this cover's origin from the "Stewart Find", which consisted of hundreds of stampless covers from the 1840s and 1850s to and from William George Stewart, who served as the Mexican Vice-Consul in New York from 1848 to 1852.