The Measurement of Permeation Velocities

The usual high vacuum technique employed in studying sorption equilibria and kinetics may be used in obtaining the permeability of metals (15,19). In addition a special problem arises, the mounting of metal membranes in a manner which will be vacuum-tight and which will permit of heating the specimen to high temperatures. 

In other arrangements tubes of the metal may be heated in a furnace. One end of the tube is closed and the other is open to a manometer. The whole tube may be surrounded by the diffusing gas. This very simple and useful method was used by Borelius and Lindblom(52). 

The pressure on the high-vacuum side may be given by mercury manometers, McLeod gauges, or Pirani gauges according to the rate at which the pressure rises on this side. At Kg. 48. Apparatus for mea-high pressures robust methods of through 

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