William Thomson, Lord Kelvin (June 26, 1824 - December 17, 1907) was a mathematical physicist and engineer. He did important work in the mathematical analysis of electricity and formulation of the first and second laws of thermodynamics, and did much to unify the emerging discipline of modern physics. He is widely known for realizing that there was a lower limit to temperature, absolute zero; absolute temperatures are stated in units of kelvin in his honor. He invented several instruments to improve navigation and safety. One notable example was a mariner's compass more accurate than any other in existence. Despite offers of elevated posts from several world renowned universities he refused to leave Glasgow, remaining Professor of Natural Philosophy for over 50 year. In the winter of 1860-1861 Kelvin slipped on ice and fractured his leg, causing him to limp thereafter. He died in 1907 at the age of 83. He was buried at Westminster Abbey near the final resting place of Isaac Newton.