John Peter Gassiot (1797-1877), British businessman and amateur scientist. Gassiot was born in London, and joined the Royal Navy as a young midshipman. After his service, in 1822 he created a firm selling cigars and port with Sebastian Gonzalez. He built a laboratory at his home to indulge his interest in electricity. His main work was with electrical discharges, and in 1841 was elected fellow of the Royal Society. Later he was the first to show that electrical discharges in thin gases may be deflected by magnetic and electrostatic influence, work which later led to the concept of cathode rays.