The damping and frequency of oscillations in liquid level between two open reservoirs of helium II connected by film has been observed to change with time following level equilibration. A maximum in the damping was found to coincide with a maximum in $\dot{\nu }$. The change in frequency is interpreted as a change in the thickness of the film, a change in ${\rho }_s$, or both.

The two-fluid critical mixing point in ${\mathrm{He}}^3$ - ${\mathrm{He}}^4$ differs from ordinary critical points in that it occurs at the intersection of three lines of critical points, in a suitable variable space. A free-energy function is proposed which removes certain discrepancies between classical (Landau) theory and experimental thermodynamic measurements. Certain solid-state transitions (e.g., the metamagnetic-antiferromagnetic transition in Fe${\mathrm{Cl}}_2$) are thermodynamic analogs of critical mixing in ${\mathrm{He}}^3$ - ${\mathrm{He}}^4$.

Raman scattering was used to probe the phase transitions of the nematic liquid-crystalline material, $p$-azoxydianisole. The intensities of several Raman modes were shown to change abruptly at the phase transitions, but no detectable frequency shift of any mode was observed. Our results suggest that the Raman spectrum of $p$-axoxydianisole is only affected by short-range ordering. Qualitative interpretation of the results is given.

Spatial variations of floating potential and density are reported for a toroidal octupole. Large scale convective structures are observed. A definite correlation is observed between known magnetic perturbations and the density-potential structures, as well as between these structures and the azimuthal variations in plasma loss.

Deuteron trajectories have been calculated for the crossed electric and magnetic fields generated by a rapidly constricting current distribution in a $z$-pinch discharge. The results show that many ions are accelerated to high energies with a large value for their time-averaged axial velocity. A neutron-production model based upon nuclear collisions by these deuterons easily accounts for the observed characteristics of neutron emission.

We have measured precisely the transport properties of a pure polycrystalline specimen of chromium, with a residual resistivity ratio of 380, from 300 to 320 K. We have found no evidence whatsoever for the 5% peak in the thermal conductivity recently reported by Meaden, Rao, and Loo.

Dynamic scaling laws for anisotropic magnetic systems are derived where the anisotropy parameters are explicitly treated. The approach is applied to calculate the critical spin relaxation rates for Heisenberg ferromagnets and antiferromagnets with one, two, and three easy axes of magnetization at $T>~T_c$.

Calculations are presented for the properties of the three-nucleon system below the three-body breakup threshold, using simple, static, central potentials which fit the $s$-wave scattering lengths and effective ranges for nucleon-nucleon scattering.

The Schrödinger-type equation for odd-parity perturbations on a background geometry has been extended to the even-parity perturbations. This should greatly simplify the analysis for calculations of gravitational radiation from stars and from objects falling into black holes.

An ac-Josephson-effect determination of $\frac{e}{h}$ has been made using a new method. The accuracy of the result referred to the local voltage standard is 0.13 ppm. The accuracy referred to the National Bureau of Standards as-maintained volt is 0.46 ppm. The final value is $\frac{2e}{h}=483.593\mathrm{}65\pm 0.00022$ MHz/μ${\mathrm{V}}_{69\mathrm{N}\mathrm{B}\mathrm{S}}$ (0.46 ppm).

Measurements made at an altitude of 40 km with a balloon-borne radiometer that has three separate spectral responses in the spectral region below 20 ${\mathrm{cm}}^{-1\mathrm{}}$ indicate that the spectrum of the isotropic background radiation may not be thermal.

From an analysis of electron production in the CERN neutrino spark-chamber experiment, it is concluded that the cross section for neutrino-electron scattering is less than $40{\sigma }_{V-A}$ with 90% confidence.

We have searched for an asymmetry in the inelastic scattering of electrons from a polarized proton target in the region of resonance excitation, at values of four-momentum transfer squared of 0.4, 0.6, and 1.0 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. Data were also taken using an incident positron beam in order to distinguish any possible effect of time-reversal invariance violation from that due to higher-order (${\alpha }^3$) contributions to the scattering. No sizable violation of time-reversal invariance was found.

We have measured the asymmetry in the elastic scattering of electrons from a polarized proton target. An interference between the imaginary part of the two-photon-exchange amplitude and the one-photon-exchange amplitude could produce a polarization effect. The results indicate no asymmetry within the experimental accuracy of 1 to 2% at four-momentum-transfer-squared values values of o.38, 0.59, and 0.98 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$.

A semiclassical model for inelastic and elastic proton-proton scattering is presented. A fit to recent $\pi$ production counter data is made. The resulting proton-proton elastic scattering and proton electromagnetic form factor are discussed. Reasonable agreement with the data is obtained.

We calculate the high-energy amplitude in quantum electrodynamics and scalar electrodynamics, and find that the Pomeranchon is a moving Regge pole near $J=\frac{3}{2}$ when $t$ equal to or near the two-particle threshold, and is a fixed branch point at $J=1\mathrm{}$ for $t<~0$. This is due to the promotion from 1 to $\frac{3}{2}$ for the power of $s$ of the tower-diagram amplitudes at threshold. The Gribov paradox is thereby automatically resolved.

Laboratory detection of a microwave absorption in ${\mathrm{H}}_2^{18}$O near 5.33 cm is reported. This observed signal has been assigned to a pure rotational transition between the $6_{16}$ and $5_{23}$ levels in the ground vibrational state of ${\mathrm{H}}_2^{18}$O. Signals from these same two rotational levels for ${\mathrm{H}}_2^{16}$O have been detected in emission from several sources in the galaxy.

We report the low-loss propagation, peak amplification, and multiple breakup of a coherent laser pulse undergoing self-induced transparency by interacting with two nondegenerate levels of a highly absorbing gas of Rb atoms. These results are in good agreement with computer solutions of coupled Schrödinger and Maxwell equations including relaxation.

Ortho-para transitions have been observed directly in C${\mathrm{H}}_4$ for the first time. These normally forbidden transitions were observed in the ground electronic, ground vibrational, and $J=2\mathrm{}$ rotational state by combining a simple level-crossing technique with the conventional molecular-beam magnetic-resonance method. It is shown how this spectrum can be used to measure, for certain tetrahedral molecules, the interaction constants which appear in the Zeeman, nuclear-hyperfine and rotational-distortion Hamiltonians.

High-resolution neutron-scattering measurements have been made of long-wavelength-phonon energies $\hslash \omega$ in liquid helium at 1.1 °K as a function of wave vector $Q$. The results are approximately described by $\omega =cQ(1-\gamma {\hslash }^2{Q}^2-\delta {\hslash }^4{Q}^4)$, with $\gamma$ very small (<2×${10}^{36}$ ${\mathrm{g}}^{-2\mathrm{}}$ ${\mathrm{cm}}^{-2\mathrm{}}$ ${\sec }^2$) and $\delta =(2.4\mathrm{}\pm 0.2)\times {10}^{75}$ ${\mathrm{g}}^{-4\mathrm{}}$ ${\mathrm{cm}}^{-4\mathrm{}}$ ${\sec }^4$.