In 1905 Lord Kelvin (1824-1907 was awarded the second John Fritz Medal for a lifetime of outstanding achievements in science and technology. I sketch Kelvin's life, education, and work in thermodynamics, electrical technology, and instrumentation, and his role in the laying of the Atlantic cable. I then turn to Kelvin's four visits to America, in 1876 on the centenary of the Declaration of Independence of the United States of America; in 1884 when he gave his famous Baltimore Lectures at The Johns Hopkins University; in 1897 when he visited Niagara Falls for the third time and advised George Westinghouse (1846-1914) on how to develop its enormous water power for the generation of electricity; and in 1902 when he advised George Eastman (1854-1932) on the development of the photographic industry.