Harald became the first of the Bohr brothers to earn a master's degree. Niels earned his 9 months later. The students in his class had to present a thesis on a topic assigned by their advisor. Bohr's supervisor was Christiansen and the subject he gave them was the electronic theory of metals. Bohr then elaborated his master's thesis into his much broader theoretical “Doctor of Philosophy” thesis. He questioned the literature on the subject, settling on a model assumed by Paul Drude and elaborated by Hendrik Lorentz, which stated that electrons on a meta; they are considered to behave like a gas. Bohr expanded Lorentz's model, but still failed to explain singularities such as the Hall effect, and decided that the electron theory could not fully explain the magnetic properties of metals. The theory was formulated in April 1911, and Bohr conducted his defense in May of that year. Bohr's thesis was innovative, but did not attract much attention outside Scandinavia because it was written in Danish, a requirement of the University of Copenhagen at the time. In 1921 the Dutch physicist Hendrika Johanna van Leeuwen independently derived a theorem from Bohr's theory, now known as the Bohr−van Leeuwen theorem. In 1911 Bohr traveled to England, where most of the theoretical work on the structures of atoms was being done. He met JJ Thomson of the Cavendish Laboratory and Trinity College, Cambridge. He attended lectures on electromagnetism given by James Jean and Joseph Larmor and decided to do some research on cathode rays, but failed to impress Thomson. He was more successful with younger physicists such as the Australian William Lawrence Bragg and the New Zealander Ernest Rutherford, whose 1911 Rutherford atom method had challenged... middle of paper... our graveyard in the Norrebro section of Copenhagen , along with the rest of his family who had died before. On October 7, 1965, the institute was officially renamed to what it had unofficially been called: Niels Bohr Institute. Although Bohr died, his legacy did not occur. In 1912 he and Margrethe married and soon after the wedding they had children, they had 6 children. The eldest son, Christian, died in a boating accident in 1934 and another Harald died of infantile meningitis. Aage Bohr became a very successful physicist and also received a Nobel Prize in Physics in 1975 like his father. Hans Henrik became a doctor; Erik became a chemical engineer and Ernest became a lawyer. Each of the men followed in the footsteps of Bohr's men, like their uncle Harald, Ernest Bohr became an Olympic athlete, playing field hockey for Denmark in the summer of 1948 in London.