Quarantine Edinburgh and Leith, grain was from that date declared to be a non-susceptible article. About 1788 an order of the council required every ship liable to quarantine, in case of meeting any vessel at sea, or within four leagues of the coast of Great Britain or Ireland, to hoist a yellow flag in the daytime and show a light at the main topmast head at night, under a penalty of After 1800, ships from plague-countries (or with foul bills) were enabled to perform their quarantine on arrival in the Medway instead of taking a Mediterranean port on the way for
Maritime flag head of the ship. These are usually flown while not underway and when the ship is dressed on special occasions. Jacks in the Royal Navy must be run up when the first line is ashore when coming alongside. On 16 January 1899, commissioned ships of the United States Coast and Geodetic Survey were authorized to fly their own flag to distinguish them from ships of the United States Navy, with which they shared a common ensign. Although they continued to fly the same ensign as U.S. Navy ships, ships of the Survey flew the Coast and Geodetic Survey flag as