A technique designed in this laboratory for the measurement of virial coefficients by pressure measurements of condensable fluids was extended to fluids not easily condensable with liquid nitrogen. Preliminary analysis using a new technique was made with data obtained from previous studies. Confirmative measurements for the procedure were made for n-butane and reported in the temperature range of 308.15 K to 348.15 Kat 10 degree intervals and at sub­atmospheric pressures. It was shown that confidence intervals in the estimation of uncertainties in these measurements are greatly improved as a result of the methodology employed, while at the same time, the results agreed very well with those reported in the literature.

Parallel studies to investigate the compression of natural gas systems were also conducted. The carbon dioxide + hydrogen system, the methane + nitrogen system together with the ternary system of carbon dioxide + nitrogen + methane were investigated in the temperature range of 303.15 K to 348.15 K using a direct method. The results agreed very well with available literature values, and in other cases fill in gaps in existing data banks.

Finally, the McGlashan-Potter [1962] correlation was revisited. Some modifications leading to the use of the correlation to estimate some volumetric properties of mixtures of non-hydrocarbons, non- "simple" or "normal" fluids and other substances for which the correlation was not originally designed for was attempted.