The viscosities of argon, methane, and ethane are reported over a temperature range from ",210 0 K to "'475°K. In conjunction with second virial coefficient data, the viscosities have been employed to estimate the potential parameters for an Exp:6 potential. For the spherically symmetric molecules a single set of parameters served to reproduce the equilibrium and transport properties with serviceable accuracy. For ethane the procedure failed, and this failure was taken as further evidence for the fundamental inadequacy of the assumptions of central forces and elastic collisions.

To facilitate the calculation of the thermodynamic properties of internal rotators lying outside the limits of available tabulations, methods of determining the energy levels are studied for the purpose of finding the most expeditious route to accurate results. It proves to be unnecessary in any case to calculate many levels from the wave mechanics. A partition function is set up in terms of the correct ground state and a series of approximate levels derived from the old quantum theory, and this is corrected to constancy by the successive substitution of correct levels, starting with the first excited state. A set of levels obtained in this way which gives the correct partition function always leads to correct values of all the thermodynamic properties. To obtain accurate energy levels, the continued fractions of Koehler and Dennison are recommended as most convenient.

o-Phenylenediacetamide has been cyclized pyrolytically to o-phenylenediacetimide. The yield at 295" was 57% on a 190-mg. scale and 53% on a 2-g. scale, while less satisfactory yields were obtained at higher or lower temperatures. About 10% of the diamide was recovered. Attempts to improve the yield by conducting the reaction under dilution in boiling phenyl ether (ammonia evolution 87%, imide recovered 12%) and in boiling phenol (ammonia evolution slow) were not successful.This apparent contradiction of the dilution principle has a fairly satisfactory explanation. If it is assumed that only amide linkages are formed and that the system is approaching equilibrium, there should be in a single phase a distribution of cyclic polymers whose mean molecular weight would decrease with increasing temperature or with dilution. The distribution, because of these two factors, should be about the same in the pyrolysis (higher temperature) and in the phenyl ether experiment (dilution). The pyrolytic reaction produces the better result because the product, along with a smaller quantity of the diamide, sublimes out of the sphere of reaction. It is possible, but less probable, that the

Data on the influence of phosphates, sulfates and arsenates on the dissolution of aged colloidal aluminum hydroxide in 0.2 N hydrochloric acid, have been presented.2. Within certain limits, the amount of the hydroxide dissolved is a logarithmic function of the concentration of the electrolyte yielding bivalent and trivalent anions. The equations take the form = K log a + C.3. The influence of the anion of higher valence is attributed to adsorption at the solid-liquid interface which produces a reduction in the electrical potential difference.4. The findings are not in accord with the diffusion theory of reactions in heterogeneous systems.

Limiting low pressure gaseous heat capacities are measured with a band-wire type thermal conductivity cell and a Knudsen pressure gage. The spectroscopic heat capacities of nitrogen and methane and the accurately known heat capacity of ethane are reproduced at 279°K. within the estimated uncertainty of ±1.0%. The Knudsen gage provides some extension of the scope of the thermal conductivity heat capacity method to compounds of higher molecular weight and lower volatility and yields measurements which should be substantially independent of adsorption and gas imperfection errors.