The most extensive series of sailing directions is that published by the British Admiralty, comprising fifty-six volumes and including all the navigable regions of the world. In the United States the Coast and Geodetic Survey publishes ten volumes of coast pilots for the Atlantic, Gulf, and Pacific coasts, Porto Rico, and southeastern Alaska, and eight volumes of sailing directions for Alaska and the Philippine Islands. The United States Hydrographic Office publishes sixteen volumes of sailing directions for various parts of the world. #Notices to Mariners# are published at frequent intervals, giving all important corrections, which should be at once applied by hand to the charts, such as rocks or shoals discovered and lights and buoys established or moved. New charts, new editions, and canceled charts are also announced. These notices should be carefully examined and the necessary corrections made on all charts of the sets in use on the vessel. A chart should be considered as a growing rather than a finished instrument, and constant watchfulness is required to see that it is kept up to date. Neglect of this may cause shipwreck, as the following instance shows. Report came to Manila in 1904 that there was a low sand islet lying off the very poorly charted northeast coast of Samar; this information was promptly published in the local Notice to Mariners. About a month later a small steamer was sent to land some native constabulary on that coast. The captain failed to obtain or observe this notice, and approached the coast before daylight on a course which led directly across the sand islet. The vessel was driven far up on the sand, where it still lies. In the United States, weekly Notices to Mariners are published by the Department of Commerce and Labor for the coasts under the jurisdiction of the United States, and by the Navy Department for all regions. These notices are distributed free and can be obtained from chart agents and consular officers. In Great Britain the notices are published at frequent intervals by the Hydrographic Office, and practically all countries issuing charts also issue such notices. Information as to important changes in lights and other announcements of navigational interest are also sometimes printed in the marine columns of newspapers and in nautical periodicals.