Sir William Snow Harris (1 April 1791 – 22 January 1867) was a British physician and electrical researcher, nicknamed Thunder-and-Lightning Harris, and noted for his invention of a successful system of lightning conductors for ships. It took many years of campaigning, research and successful testing before the British Royal Navy changed to Harris's conductors from their previous less effective system. One of the successful test vessels was which survived lightning strikes unharmed on her famous voyage with Charles Darwin.