A set of overstable modes is found for a low-$\beta$ current-carrying plasma having high gradients of resistivity. It is suggested that these modes provide an explanation for the large-amplitude spontaneous oscillations that have been observed in a fully ionized current-carrying plasma column.

$\theta$ pinching was observed in intrinsic InSb (250°K) by measuring the time derivative of the magnetic flux in the sample.

Photoemission measurements of the optical density of states in In are found to be in good over-all agreement with the density of states deduced from the nearly-free-electron model by use of a pseudopotential consistent with Fermi-surface data. A slight scaling of the energy, in accord with effective-mass data, is required.

Observations of harmonic scattering (second-harmonic generation) by fluctuations in angular orientation are reported for polycrystalline N${\mathrm{H}}_4$Cl for temperatures in the immediate vicinity of the second-order phase transition at ∼242.4°K. Harmonic intensities were found to decrease exponentially within the range $2\times {10}^{-4\mathrm{}}<~\epsilon <2\mathrm{}\times {10}^{-2\mathrm{}}$, where $\epsilon =\frac{T}{T_c}-1\mathrm{}$. The results, together with suitable assumptions, are used to obtain an estimate of the variation of the long-range correlation parameter ${\kappa }^{-1\mathrm{}}$ with $\epsilon$, with results different from those expected.

From the terrestrial occurrence of the nuclei ${\mathrm{Re}}^{187}$ and ${\mathrm{Os}}^{187}$, it is deduced that the elementary unit of charge $e$ cannot have varied by as much as one part in 1600 during the history of the earth.

The fine structure constant at red shifts $\frac{\Delta \lambda }{\lambda }\approx 0.2$, corresponding to an epoch around two billion years ago, has been determined using the wavelengths of a pair of O III emission lines measured in the spectra of five radio galaxies. We find $\frac{\alpha \mathrm{}(z=0.2\mathrm{})\mathrm{}}{\alpha \left(\mathrm{lab}\right)}=1.001\mathrm{}\pm 0.002$ probable error.

The usual interpretation, in Regge-pole models, of the change in signs of the cross section differences $\frac{d\sigma \left(\overline{A}B\right)}{\mathrm{dt}}-\frac{d\sigma \mathrm{}\left(\mathrm{AB}\right)\mathrm{}}{\mathrm{dt}}$ at $t\sim -0.15\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ observed in elastic $\pi N$, $\mathrm{KN}$, and $\mathrm{NN}$ scattering is inconsistent with recent data on the reaction $\gamma p\to {\pi }^{0}p$. It is pointed out that this contradiction is direct evidence for the existence of contributions to the high-energy scattering amplitudes in addition to those of the leading Regge poles. Alternative explanations of the crossover phenomena which avoid the foregoing difficulty are proposed, and their implications are discussed.

The contribution of Mandelstam branch cuts to the processes $p+p\to p+p$, $p+K\to p+K^{*}$, $p+\gamma \to p+\pi$, and $p+\pi \to p+A_2$ is investigated by considering the structure of diagrams in which two or more Reggeons (asymptotic Regge-pole amplitudes) are exchanged. Three or more Reggeons are required for the forward nucleon-nucleon scattering amplitude ${{\sigma }_x}^{\mathrm{}\left(1\right)\mathrm{}}{{\sigma }_x}^{\mathrm{}\left(2\right)\mathrm{}}+{{\sigma }_y}^{\mathrm{}\left(1\right)\mathrm{}}{{\sigma }_y}^{\mathrm{}\left(2\right)\mathrm{}}$, and for the forward production amplitudes. These amplitudes are expected to behave asymptotically as $\frac{s}{{\left(\ln s\right)}^5}$.

The amplitude for $\omega +\pi \to \pi +\pi$ is considered within a dynamical scheme proposed by Mandelstam, based on rising Regge trajectories, the narrow-resonance approximation, and generalized superconvergence relations. The $\rho$ trajectory is shown to qualitatively bootstrap itself. Also, a world consisting only of the particles on a vacuum trajectory is shown to be inconsistent within this approximation.

The thickness of a rotating liquid-helium film has been measured at various angular velocities and temperatures. The results are consistent with hydrodynamical calculations assuming that the superfluid component remains at rest and that the normal component alone rotates. The failure to induce rotation in the superfluid component is interpreted as evidence that vortex lines with their axes perpendicular to the film are difficult to create.

A linear shift of the epr lines of ${\mathrm{Cu}}^{2+}$ -doped Rochelle salt by an applied electric field has been observed in the high-temperature paraelectric phase. The shifts become asymmetric with respect to the polarity of the applied field in the ferroelectric phase and disappear at low temperatures in the antiferroelectric phase, demonstrating that it is only the instability of the crystal lattice connected with the ferroelectric transitions which makes the electric-field effect easily observable.

We present magnetic-moment measurements in polycrystalline and single-crystal Zr${\mathrm{Zn}}_2$ for fields to 150 kG. The high-field susceptibility is identical for all materials whereas the low-field moment varies over a wide range. The data indicate that the low-field moment is correlated with trace impurities (such as Fe and Ti) and details of preparation. We suggest a localized-moment model for ferromagnetism in impure Zr${\mathrm{Zn}}_2$ which is consistent with our results; but it is not yet clear whether or not "pure" Zr${\mathrm{Zn}}_2$ is ferromagnetic.

The upper critical field $H_{c2\mathrm{}}$ for a Type-II two-band superconductor is investigated in the pure limit. Near $T_c$, $H_{c2\mathrm{}}$ is dominated by the $s$ band, whereas the thermodynamic properties are determined by the $d$ band. A modification to the Gor'kov theory is found for the ratio of $K_1\mathrm{}\left(T\right)\mathrm{}$ at $T=0\mathrm{}$ and $T=T_c$. This result may explain the discrepancy between the one-band theory and experimental data.