National Geographic : 1920 Feb
REAR-ADMIRAL JOSEPH STRAUSS AND HIS STAFF ON BOARD HIS FLAGSHIP, THE "BLACK HAWK" Left to right: Lieut.-Commander Noel Davis, Rear-Admiral Joseph Harrill, and Ensign K. C. Richmond. Strauss, Lieut. W. K. MARKER BUOYS TO INDICATE THE POSITIONS OF THE LINES OE MINES WERE PLACED AT INTERVALS OE THREE MILES THROUGHOUT THE LENGTH OP EACH GROUP Besides a differently arranged flag, each buoy was painted to show which line of mines it marked and its position in the group, in much the same manner that the signs on the street corners indicate the streets. The buoys were assembled on board, using the sphero cylindrical cans which are seen on the stern of the ship.