A review is given of the techniques for detection of 10- to 30-Mev monoenergetic neutrons with emphasis being placed on absolute neutron flux measurements. Charged particle reactions, which result in monoenergetic neutrons, are discussed; the published cross-section data for the neutron producing reactions involving the hydrogen isotopes are collected and presented as a function of energy and angle. Sources of background neutrons are considered. Tables of neutron energies including relativistic effects for the hydrogen isotope reactions are presented.

The density of the air in the atmosphere, or of the water in the ocean, is a function of altitude or depth. Linear equations for the motion of such stratified fluids have been derived by many authors. Many have introduced simplifying assumptions into their derivations, with the result that it is difficult to compare one paper with another. The present review is a collection of the major systems of equations, in a uniform notation. The derivations given are those which bring out the interrelations of the various systems, and are sometimes quite different from those of the original papers. The solution of the equations is not discussed, so that the relative merits of the various systems cannot be evaluated.

Modified Sargent diagram of $K$-electron capture transitions of odd nuclides with $Z\le 60$ shows an allowed transition band with superallowed transitions well above the first-forbidden transitions below it. Correspondingly the histogram of $log\mathrm{ft}$ values of these transitions shows a peak in the range of 5 to 6.

A number of methods, suitable for computation of Coulomb wave functions with high accuracy, are collected, most of them previously well known. It is shown that the regions where these methods can be used, together cover all positive values of $\rho$ and $\eta$ in the case $L=0\mathrm{}$. All formulas are presented in a form well adapted for direct numerical computation.

The 1952 data used by DuMond and Cohen in an evaluation of the atomic constants are analyzed for the presence of systematic errors by a variance analysis performed by an electronic digital computer. For simplicity the velocity of light is treated as a fixed constant of known value and there remain then eleven linear equations in four unknowns subject to least-squares adjustment. Least-squares adjustments of 219 over-determined subsets of these equations have been made and ${\chi }^2$ has been evaluated for each such subset. An analysis of these data indicates that small systematic errors are most likely to exist in the following input data: (1) The determination of the Faraday by the silver voltameter. (2) The determination of the cyclotron resonance frequency of the proton by the inverse cyclotron method of Bloch and Jeffreys. (3) Certain of the higher voltage determinations of $\frac{h}{e}$ by the continuous x-ray quantum limit. In descending order of magnitude of discrepancy from the remaining data on the constants are the determinations of (a) Felt, Harris, and DuMond made at 24 500 volts, (b) Bearden and Schwarz at 19 600 volts, (c) Bearden and Schwarz and also Bearden, Johnson, and Watts in the region between about 10 kv and about 6 kv. An analysis of the various observations taken by these observers at different voltages reveals a possible systematic trend when discrepancy is plotted against either voltage or window width in volts. Conjectures to account for the effect are discussed.

The modifications called for by this analysis yield a new 1955 adjustment in which ${\chi }^2$ is smaller than it was for the November, 1952 adjustment. The new ${\chi }^2=3.25\mathrm{}$ is satisfactorily close to its expected value, 3. Thanks to the fact that the error measures adopted in the November, 1952 adjustment for the output values were conservatively based on the criterion of external consistency, the changes in the values occasioned as a result of the present analysis are all well within those estimated limits. A welcome effect of this new adjustment is that the adjusted output value of $\frac{{\lambda }_g}{{\lambda }_s}$, the conversion factor from Siegbahn's $x$-units to milliangstroms, now lies much closer to the input value. A new table of constants and conversion factors is presented.