Second virial coefficient of helium from 0 to 500°C by the two-temperature gas-expansion method

Values of the second virial coefficient of helium have been obtained from 0 to 500°C as a by-product of the determination of the thermal expansion of stainless steel vessels used for measurements of the density of water. The Burnett method was used, usually with the two vessels at different temperatures. Gas expansions were made both from the low-temperature vessel to the high and from the high to the low. Truncation problems limit the precision of B2 for one set of measurements but the temperature dependence has been found accurately. The other measurements appear free of significant systematic error.