Sir Ernest Marsden (19 February 1889 – 15 December 1970) was an English-New Zealand physicist. He is recognised internationally for his contributions to science while working under Ernest Rutherford, which led to the discovery of new theories on the structure of the atom. In Marsden's later work in New Zealand, he became a significant member of the scientific community, while maintaining close links to the United Kingdom. Education Born in Manchester, the son of Thomas Marsden and Phoebe Holden, Marsden lived in Rishton and attended Queen Elizabeth's Grammar School, Blackburn, where an inter-house trophy rewarding academic excellence ('The Marsden Merit Trophy') bears his name. In 1909, as a 20-year-old student at the University of Manchester, he met and began work under Ernest Rutherford. While still an undergraduate he conducted the famous Geiger–Marsden experiment, also called the gold foil experiment, together with Hans Geiger under Rutherford's supervision. This experiment led to Rutherford's new theory for the structure of the atom, with a centralised concentration of mass and positive charge surrounded by empty space and a sea of orbiting negatively charged electrons. Rutherford later described this as "almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back to hit you". The apparatus used in the experiment was an early version of what was to become the Geiger counter. In 1915 he moved to Victoria University College in Wellington, New Zealand, to replace Thomas Laby as Professor of Physics; Rutherford recommended his appointment there. Career Marsden served in France during World War I as a Royal Engineer in a special sound-ranging section and was awarded the Military Cross in the 1919 King's Birthday Honours. In 1922 Marsden turned from his research and position as Professor of Physics to bureaucracy. He was appointed Assistant Director of Education before accepting the position of Secretary of New Zealand's new Department of Scientific and Industrial Research (DSIR) in 1926. The new Department's focus was on assisting primary industries, and Marsden worked to organise research particularly in the area of agriculture. Marsden initiated a number of projects that kept New Zealand in touch with international developments in the field of radiation and nuclear sciences. In 1939 he pioneered the non-medical use of radioisotopes in New Zealand, and conducted a series of experiments to determine the role of cobalt in animal metabolism. With the outbreak of World War II