The spectra of thermal neutrons were measured in water at various distances from a spherical source, in order to determine the temperature of the neutron gas. The spectrum of the source was obtained by means of the cadmium difference; it exhibited a Maxwellian distribution and a temperature exceeding considerably the temperature of the water, which acted as the moderator for the collimated beam from the reactor. The beam was directed onto the water container by means of a tube which terminated in the center of a 40-mm diameter Pb sphere, serving as the source. The chopper used for the measurements had a resolution of about 40 mu sec per meter at 3000 rpm and a flight path of 3 m. The results obtained by means of a 256channel analyzer showed that at a distance larger than 20 mm from the sphere, the experimental points agree well, within ihe limits of the experimental error, with the Maxwellisn distribution at the temperature of the medium. At shorter distances, the anisotropy caused by hot'' neutrons becomes noticeable. The following neutron temperatures were obtained: 317 plus or minus 15 deg K for 10 mm, 360 plus or minus 28 deg K for 5 mm,more » and 500 plus or minus 28 deg K for 0 mm. The neutron gas temperature was computed by solving the kinetic equation. (TTT)« less