All of the available evidence leads to the view that the 5f electron shell is being filled in the heaviest elements giving rise to a transition series which begins with actinium in the same sense that the rare earth or 'lanthanide' series begins with lanthanum. Such an 'actinide' series is suggested on the basis of evidence in the following lines: (1) chemical properties, (2) absorption spectra in aqueous solution and crystals, (3) crystallographic structure data, (4) magnetic susceptibility data and (5) spectroscopic data. The salient point is that the characteristic oxidation state (i.e., the oxidation state exhibited by the member containing seven 5f and presumably also by the member containing fourteen 5f electrons, curium and element 103) is the III state, and the group is placed in the periodic table on this basis. The data also make it possible to give a suggested table of electronic configurations of the ground state of the gaseous atom for each of the elements from actinium to curium inclusive.

On July 14, 1949, and office memorandum was written about operations of a reprocessing building on the Hanford Site being suspended due to the mishandling of some plutonium powder. The letter describes the process of decontamination of the building surfaces, and the ventilation of the rooms of that building. It also describes the problem with the ventilation fans due to increased temperature and pressures.

This paper contains a description of the apparatus and theories of the methods successfully used for determining the fast decay periods of near-critical assemblies. The methods described are: (1) the modulation method and (2) the delayed coincidence or Rossi method