Report discussing tests conducted in an attempt to adapt a micromanometer for use in measuring variations of about 0.003 mm Hg in atmospheric pressure. Additionally, a method for making full use of the micromanometer sensitivity and extending its range is described.

This paper presents the results of a series of buckling measurements involving the use of enriched uranium rods (1.007% by weight U²³⁵) in light water. The effect of replacing a water reflector with one of uranyl nitrate solution of two different concentrations, 536 and 188 grams of U per liter of solution was investigated for the 0.925" rods with the 1.74 H₂O/U-volume ratio in the core. Some information was also obtained on the extrapolation length to be used in unreflected cases. The application of theory to these lattices, and others, is given in an appendix under separate title, "Buckling Calculations for One Per Cent Enriched Uranium-Water Rod Lattices."

A general method is developed to allow calculation of the critical buckling of an assemblage of fissile regions coupled by neutron leakage. Consideration is given both to regions embedded in vacuum and in material media. Several cases of simple geometry are further developed to illustrate the theory.