Twenty-two compressibility runs were made with helium over the temperature range -5℗ʻ to 80 ℗ʻ Celsius and at pressures to 800 atmospheres. A Burnett apparatus was used. Data from the runs were fitted to a fourth degree polynomial equation in the pressure and weighting factor of Pŕ℗đ/́þ was used. All data for a particular isotherm were treated simultaneously.