The phase boundary of the binary liquid system CS₂+CH₃NO₂ is studied over nearly six decades in reduced temperature 3×10⁻⁶<ε=(T_C−T)/T_C<2×10⁻¹ and over the composition range 8-98 mole % of CS₂. The critical parameters areT_C=335.13₂K andx_C=57.3₄ mole % of CS₂. A single critical exponentβ=0.315±0.004 fits the observations over the entire range with no indication ofβ increasing to the classical value of 1/2 far away fromT_C. The diameter of the coexistence curve shows a rectilinear behaviour only far away fromT_C. NearT_C, the deviation ΔX from the rectilinear law seems to fit a curve of the form ΔX=fε^7/8 exp (−gε^h), the derivative of which has a singularity like that of specific heat. An ambiguity in the analysis of the data in terms of mole fractions and volume fractions is pointed out. It is also suggested that the curvature of the diameter may be much weaker in a liquid-gas system and hence might have escaped detection.

Electrical resistance measurements are reported on the binary liquid mixtures CS₂ + CH₃CN and CS₂ + CH₃NO₂ with special reference to the critical region. Impurity conduction seems to be the dominant mechanism for charge transport. For the liquid mixture filled at the critical composition, the resistance of the system aboveT_c follows the relationR=R_c−A(T−T_c)^b withb=0·6±0·1. BelowT_c the conductivities of the two phases obey a relation σ₂−σ₁=B(T_c−T)^β with β=0·34±0·02, the exponent of the transport coefficient being the same as the exponent of the order parameter, an equilibrium property.

The details of experiments showing the effects of self-pumped phase conjugation on reflection and on transmission in barium titanate crystal are given. The specular reflection and the second-surface reflection of an extraordinary polarized beam, incident on the face of the crystal parallel to itsc-axis, get reduced in intensity as the phase conjugation develops. It has been found that parts of the self-pumped phase conjugate beam emerge out of the crystal as additional transmission beams. They grow in intensity as the phase conjugation develops. Other measurements which combine coherent or incoherent coupling beams are presented and used to explain the observations.