Abstract: "Using xylene as the densimetric solvent, the crystal densities have been determined by the pyknometric method for the following chlorides, UCl3, UCl4, UCl6(UCl4), UCl6 and U02Cl2."

Report discussing the progress made on a research project for the preparation of ductile zirconium during April 1949.

Abstract: "This paper gives an arithmetic method of computing the number of sections required in a catalytic tower to produce a given enrichment. It also tells how to calculate the enrichment of a tower with a given number of sections. The problem of the most economical design of catalytic towers is solved. Methods are given for determining the temperature, the efficiencies of catalyst beds and strippers, the relative production rate, and the water vapor-hydrogen gas ratio which give the optimum combination of operating pressure, cross sectional area, number of sections, and volume of catalyst in the tower. Simple directions as to how to make the calculations are included."

Purpose: "To study the value of electrical induction methods for the measurement of liquid and interface levels."

This report describes the use of pile control over atomic power, including the different methods of control.

Report discussing procedures for analyzing the quantity of plutonium in stool samples. Ashing methods are described, as well as methods for extraction of plutonium from the stool.

Technical report covering (1) analysis of uranium bromide and chloride samples, (2) the ferric-nitrate method of analyzing uranium fluorides for fluorine, (3) spectrographic determination of boron, cadmium and manganese in magnesium metal, (4) service analyses. contributions to other problems, (5) attempted preparation of uranous oxyfluoride, and (6) corrections in previous reports.

Technical report includes three reports of research progress: 1)Meson Mass Determination by Grain Counting, W. H. Barkas; 2) The Magnetic Beta Ray Lens Spectrograph, A. C. Helmholz; 3) Anthracene Counters, E. Martinelli.

The absolute excitation functions for the production of fission by charged particle bombardment in several substances were investigated at both high and low energies. The low energy work was done at the 60-inch Crocker cyclotron with alpha particles and deuterons, while the high energy work was done at the 184-inch cyclotron with alpha particles, deuterons, and protons.

A diffusion pump having a rectangular mouth 1' by 3' in the vertical plane, employing linear jets.

Apparatus, field layout, miscellaneous testing, and the method of analysis of a 100-ton test at Trinity.