COSTON LIGHT, a pyrotechnic light designed for night signalling between vessels at sea and between sea and shore. The signal is made in the form of a cartridge containing slow-burning chemicals which produce an intense light, in various colour com binations. The cartridge is mounted on a cylindrical wooden base adapted to be inserted in a holder equipped with a brass ferrule to receive it, and a plunger for igniting the signal by means of a percussion cap, in much the same manner as a shell is exploded by the trigger of a gun. In clear weather these signals can be seen for a distance as great as Ism. and have exceptional penetra tion in mist or fog. The signals are so constructed that they will show successively various colours—blue, green, red, yellow and white—and various combinations of these are extensively used by steamship lines as distinguishing night signals. This signal was adopted by the U.S. Life-Saving Service (now Coast Guard) in 1873, for use by the beach patrol at night and in thick weather to give notice upon discovery of a wreck or vessel in distress that they are seen and help is at hand, and to warn vessels running dangerously near the shore.