抄録
A simple torsion-type microbalance with a sensitivity of 6. 6 ×10-7 gw/deg was constructed in which the beam, having a vertical vane at one end and a counterbalance at the other, was allowed to oscillate in a horizontal plane. Silver was evaporated so that the vapour atoms impinge the vane normally, and the pressure exerted on the vane p (dyn/cm2) determined. The deposition rate r (g/cm2·S) was measured simultaneously by means of a crystal-oscillator. The ratio p/r gives the mean velocity <υ> of the vapour atoms. The obtained values of <υ> are a little larger than those calculated on the assumption that the vapour atoms obey the Maxwell-Boltzmann distribution for the source temperature. The differences are presumably due partly to the geometry of the evaporation source and partly to the insufficient accuracy of the measurement.
