In order to determine whether molybdenum is a type I or type II superconductor, magnetic measurements are being undertaken. The molybdenum samples were prepared by electron-beam float-zone refining. Resistivity measurements on one sample indicated that it is of adequate purity. In initial experiments in a helium-4 cryostat, no superconductivity was observed at temperatures down to about 0.9° K. In order to reach lower temperatures, a helium-3 cryostat of the single condensation type has been built. Details of the design and results of preliminary operation are discussed. In this cryostat, superconductivity in molybdenum has been observed. At 0.65° K in an external field of 15 oersteds, magnetic induction in the sample was zero.