This pamplet is intended as an aid in the identification of mines. It is not intended for use as text book, but simply as an aid to mine watchers, beach patrols, and all ships at sea.

Floating spherical mines are usually found with approximately one third of the mine showing. However, this may vary if the case has been dented or punctured. In these in-stances the case will usually exhibit less buoyancy, and will, therefore, ride with more of its upper hemisphere awash. Mines of different nations also exhibit varying floating cha-racteristics.

If the mine is sighted at sea, an attempt should be made to identify it by comparing it as nearly as possible to a mine in this pamphlet. The "Type Number" and position of the mine should be determined, and the time of sighting should be noted. The Chief of Naval Operations (Hydrographic Office) should be notified by dispatch or, if it is necessary to maintain radio silence, by letter at the end of the voyage. Information copies of this dis-patch or letter should be sent to the nearest Naval activity, which in turn will notify the Mine Disposal Unit under its command for necessary action. If circumstances permit, it is recommended that drifting mines be destroyed by gunfire, using .50 cal. or 20 mm AP ammunition. It is possible that gunfire may explode drifting mines. Therefore, they should not be approached closer than 300 yards, and due precautions taken to protect person-nel from flying fragments. No attempt should be made to take aboard or tamper with a beached mine unless designated Mine Disposal personnel are present. The fact that these mines are dangerous to personnel and hazardous to ships cannot be overempha-zied.