The slow neutron-induced radioactivities of nuclear explosions

The slow neutron-induced radioactivities of nuclear explosions have been evaluated for infinite media of filtered Schuylkill water and the earth's crust. The magnitudes of these effects are compared with the activity of the fission fragments, and the conditions under which they may be of importance are considered.It has been assumed that a gram-molecule of neutrons is liberated in the blast.     

Theory of the halftone process. II. The diffraction theory-calculation of the light distribution

An approximate method of calculating the light distribution in the dots formed behind a halftone screen from the Fresnel diffraction theory is described, and in a typical case, the distribution is found to check closely with that determined experimentally, being very different from that calculated from geometrical optics.