"An experiment in which a nuclear emulsion stack of 25 Ilford G-5 emulsion pellicles were exposed to 925-Mev He^4 nuclei is described. The tracks of the He nuclei entering the stack were followed in the stack until they interacted or stopped. From the data the scattering constants for He^4 and He^3 were calculated."

"It is shown that in a class of models of quantum field theory, the perturbation expansion of the resolvent operator, (H - z)-1, converges for all complex z. The class of models consists of all theories with Yukawa coupling in which the vacuum polarization is neglected. The method used is that of comparison with the exactly solvable neutral solar model."

"The canonical theory of motion of a charged particle in a slowly varying, static electromagnetic field is formulated. The Hamiltonian is written down explicitly in terms of the coordinates of the gyration and the drift. The method of approach is analogous to that of the canonical formalism with subsidiary condition as used in theories of collective motion in many-body systems, such as the motion of the center of gravity. In the lowest order of the perturbation, it is shown that the Hamiltonian for the drift motion averaged over the gyration phase is given by adding to the original Hamiltonian a potential term equal to the product of the magnetic moment and the magnetic field strength."

"A kinetic study is made of a system of neutral particles which interact under gravitational forces. The Jeans instability is recaptured in the limit of long wavelengths where the growth rate assumes a characteristic maximum value. As the wavelength diminishes to a certain critical distance, the instability vanishes. This distance is consistent with thermal-gravitational estimates for the diameter of a star. Plasma oscillations are found in the central region of a one-component charged gas cloud."