#UO55 - entire - unused

A War Department official stamped envelope from the late 19th century, specifically used by the U.S. Army Signal Service for transmitting weather-related data. The U.S. Army Signal Service managed the national weather observation system from 1870 to 1890. Similar envelopes with the "Railway Bulletins" corner card were notably in use between 1884 and 1885. Official stamps and envelopes replaced "free franking" (mailing without stamps) in 1873 to curb government abuse. The War Department purchased these specialized 3-cent envelopes for its executive correspondence.