A technique has been developed to make precision measurements of the cosmic microwave background radiation with simple Dicke radiometers. A measurement made at $\lambda =8.56\mathrm{}$ mm gives a radiation temperature of ${2.56}_{-0.22\mathrm{}}^{+0.17\mathrm{}}$°K, in good agreement with new results obtained at longer wavelengths.

In an effort to delineate the spectrum of the cosmic blackbody radiation, we have made more accurate measurements of the intensity at wavelengths of 3.2 and 1.58 cm. The results, combined with that at $\lambda =8.56\mathrm{}$ mm reported in the preceding Letter, indicate that over this wavelength range the spectrum is that of a black body at ${2.68}_{-0.14\mathrm{}}$ ${}_{}{}^{+0.09\mathrm{}}{}_{}{}^{}\mathrm{°}\mathrm{K}$. In particular, a hot greybody spectrum does not fit the results.

The cross section for scattering of electrons off carbon has been measured at laboratory angles of 3.3°, 6°, and 12° for incident energies of 1 to 5 GeV. The measured cross sections are in good agreement with the sum rules describing this process.

We report measurements of the photoproduction from hydrogen of single ${\pi }^{+}$ mesons at gamma-ray energies of 3.4 and 5.0 BeV and at laboratory angles of 5.1°, 7.1°, 9.9°, and 15.1°. The $s$ dependence at fixed $t$ is derived for momentum transfers of -0.20, -0.37, and -0.70 Be${\mathrm{V}}^2$. The pion data are compared with a Reggeized one-pion-exchange model.

A recent high-precision ($p, p$) polarization measurement at 19.7 MeV from Berkeley has been phase-shift analyzed. It is not consistent with other ($p, p$) measurements at nearby energies.

We have observed a marked $\Lambda K^{+}$ enhancement centered at 1.7 GeV with a width of 0.17 GeV in the interaction ${\pi }^{-}p\to \Lambda K^{+}{\pi }^{-}$ at 6 GeV/c. This effect does not show up strongly in the similar interactions ${\pi }^{\pm }p\to \Lambda K^{+,0\mathrm{}}{\pi }^{+,0\mathrm{}}$. We discuss the production mechanism in terms of $s$ (direct) and $t$ (crossed) channels, and examine the question of whether this enhancement is associated with the ${N_{\frac{1}{2}}}^{*}\mathrm{}\left(1688\right)\mathrm{}$.

We have observed directly the time correlation between successively emitted photons in the $7{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}-6\mathrm{}{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}-6\mathrm{}{}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}$ cascade of atomic mercury, and have deduced from it direct measurements of both the natural lifetime of the $6{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$ state and the dependence of the mean correlation time (coherence time) on the density of the mercury vapor surrounding the primary radiation region. The density-dependent coherence time constitutes a direct observation of the imprisonment of resonance radiation and provides an experimental confirmation of the theory describing this phenomenon.

Stimulated Raman scattering is observed to be strongly quenched under pulse excitation with pulses shorter than the molecular rotation time, because such pulses see a smaller Kerr effect and experience less self-focusing. Reduced stimulated Brillouin emission is also observed.

A method for solving the initial-value problem of the Korteweg-deVries equation is presented which is applicable to initial data that approach a constant sufficiently rapidly as $\mathrm{}\left|x\right|\mathrm{}\to \infty$. The method can be used to predict exactly the "solitons," or solitary waves, which emerge from arbitrary initial conditions. Solutions that describe any finite number of solitons in interaction can be expressed in closed form.

A plasma has been heated substantially by passing a current through it. The plasma was injected axially into a mirror field, and the current was passed through the plasma parallel to the magnetic field. We obtained a heating efficiency, insensitive to variations of the discharge-circuit parameters as well as the density of the initial plasma, of 3-4%.

Measurements of the pressure versus temperature for constant-volume samples of solid ${\mathrm{He}}^3$ to 20 mdeg K show the expected $T^{-1\mathrm{}}$ dependence due to spin ordering at low temperatures. A value for the exchange integral $\frac{\mathrm{}\left|J\right|\mathrm{}}{k}$ of about 0.7 mdeg K is obtained for a molar volume of 24 ${\mathrm{cm}}^3$, with $\frac{\partial \ln \mathrm{}\left|J\right|\mathrm{}}{\partial \ln V}=16.4\mathrm{}$.

The periodic deviation from the Schottky effect for thermionic emission has been measured for iridium polycrystalline wire over a temperature range from 1500 to 2000°K. A least-squares computer program was used to fit the experimental data with the periodic $F_2$ term predicted by the Miller-Good theory and deduce a complex reflection coefficient for the surface potential. However, the results also indicate that the amplitude of the experimental deviation increases slightly faster with field than is predicted by theory.

The infrared reflection and transmission and Raman spectra of the mixed system $\mathrm{Zn}{\mathrm{S}}_x{\mathrm{Se}}_{1-x}$ reveal two LO and TO phonons at $\overrightarrow{\mathrm{k}}\sim 0$ for any concentration. The local and gap mode frequencies follow as extrapolations of the mixed crystal system behavior. A "sum rule" pertaining to the mixed system optical phonons is proposed.