FTP identify this British physicist best known for combining his revision of Ampere's Law with Faraday's Law and Gauss's Laws of Electricity and Magnetism to produce his four namesake "equations" governing electromagnetism.
His work explaining the instability of James Watt's fly-ball governor is regarded as the birth of modern control theory, and his mathematical analysis of the stability of Saturn's rings showed that they could be neither entirely solid nor liquid.  He showed how to calculate stresses in suspension bridges and coined the term "curl" to use in the differential form of his most famous accomplishment; however, the only other real work he did on it was the addition of a term for "displacement current."  FTP identify this British physicist best known for combining his revision of Ampere's Law with Faraday's Law and Gauss's Laws of Electricity and Magnetism to produce his four namesake "equations" governing electromagnetism.
His work explaining the instability of James Watt's fly-ball governor is regarded as the birth of modern control theory, and his mathematical analysis of the stability of Saturn's rings showed that they could be neither entirely solid nor liquid.  
James Clerk Maxwell