A method has been developed for determining absolute numbers of neutrons in terms of helium production in the B(n,&agr;)Li reaction. We are able to report preliminary measurements of the number of neutrons emitted per second from a certain Ra+Be source; i.e., source called No. 38, which contains 504 millicuries of Ra, was found to emit (5.5±0.4)×106neutrons per second.