A modification of the Bridgeman anvils is described. This modification permits studies to be made to a load of 400 kbars, about twice that previously available.

An experiment has been performed using nuclear emulsions to measure the neutron flux and energy spectrum from a thick uranium target bombarded by 18-Mev electrons. The total integrated flux of 3.6 x 10(-4) neutrons/electron found here is considerably lower than the figure reported by other investigators. We attribute this discrepancy primarily to a wandering of the electron beam. The neutron spectrum should be unaffected. In addition to the expected peak at 1 Mev the energy spectrum shows a secondary peak at about 5 Mev. The shape of the experimental spectrum excluding this secondary peak, is fitted theoretically by a combination of the "evaporative" and "resonance direct" effects.