The study of artificial radioactive isotopes is at the present time one of the most important topics in nuclear research. It involves the establishment of a detailed term scheme for the disintegration in question. Not only are the energies of the components of the different beta and gamma radiations of interest, but also their intensities. These data give information concerning the probabilities of transitions between the different nuclear energy levels. From them it is possible to draw conclusions regarding the mechanism of the disintegration and to correlate the spina and parities of the levels.

The recent interest in tributyl phosphate as an extracting solvent for uranium indicated that consideration of n-butyl phosphoric acid for this application might be of interest if some way could be devised to overcome the manipulation and miscibility difficulties. It was found that if the material was placed in any one of a number of carrier solvents, it had a remarkably strong extractive effect on uranyl ion out of acid solutions without a salting agent present.

Our knowledge of the properties of mesons and their interactions with nuclei has come from two sources. Studies of cosmic ray phenomena provided the earliest information. The discovery that mesons may be produced artificially by bombardment of nuclei with radiations from high energy accelerators has, on the other hand, made it feasible to undertake a wide variety of investigations under more controlled conditions than is possible in cosmic ray experiments. In such experiments mesons have been produced by high-energy protons, alpha-particles and neutrons.