The interaction of the neutron's magnetic moment with an external magnetic field was exploited to determine the spin of the neutron. In 1949, D. Hughes and M. Burgy measured neutrons reflected from a ferromagnetic mirror and found that the angular distribution of the reflections was consistent with spin ⁠ 1 / 2 ⁠. In 1954, J. Sherwood, T. Stephenson, and S. Bernstein employed neutrons in a Stern–Gerlach experiment that used a magnetic field to separate the neutron spin states. They recorded the two such spin states, consistent with a spin ⁠ 1 / 2 ⁠ particle. Until these measurements, the possibility that the neutron was a spin ⁠ 3 / 2 ⁠ particle could not have been ruled out.