Thomas Harris (died 25 May 1824) was a pioneering English balloonist who was killed in an accident. There is little information about his early career. He invented the first mechanism for emptying a balloon canopy of gas or hot air, thus reducing the drag on landing. He designed a double valve, located at the top of the balloon bag, with a small valve fitted inside a larger one. One was for releasing the gases slowly, the other quickly. An account of his death is given by Lionel Rolt, who states that it is likely that as gas gradually escaped from the balloon, the cord connecting the gas discharge valve to the gondola tightened, releasing the gas. In the resulting crash Harris was killed, and his passenger, Sophia Stocks, was badly injured. In a less plausible theory of the cause of the crash, the release valve got stuck in the open position, thus releasing the hydrogen. In an attempt to prevent the balloon falling, Harris threw out all the ballast and even the woman's clothes. In the end, he jumped to his death, making the balloon light enough to save his companion's life.