Martha J. Coston (1826? 1829? –1904) was an inventor and businesswoman best known for her invention of the Coston flare, a device for signaling at sea.
She was born Martha Jane Hunt in Baltimore, Maryland, and moved to Philadelphia in the 1830s. At age 14 or 16, she eloped with a Benjamin Franklin Coston, age 21, who had already acquired a reputation as a promising inventor. As a young man, he became director of the U.S. Navy’s scientific laboratory in Washington, D.C. At the Washington Navy Yard, he developed a signaling rocket and a percussion primer for cannons. He also experimented with color-coded night signals to allow communication between ships, which at that time was limited to visual signals such as flags during the day and lanterns at night. After a dispute over payment for his work on the percussion primer, Coston resigned his commission with the Navy in 1847 and became president of the Boston Gas Company. His work with chemical fumes at both the Navy Yard and the Boston Gas Company caused his health to deteriorate, and he died in 1848 as a result of the chemical exposure. His work on the signal flares, while important, was limited to plans and chemical formulas.