The Adsorption Kinetics for Molecules Attached at More than One Point.

The extremely short range of atomic forces limits the effectiveness of adsorptive forces to a region within an atomic diameter of the surface.' Furthermore, the portions of this force region directly overlying the surface atoms would be the seat of forces enormously more intense than the regions in between these atoms. Such a structure of the adsorptive forces leads to the conception that the separate atoms of the adsorbed molecule are attached to the separate atoms of the surface. Insofar as the geometric arrangement of the relevant atoms does not permit this, the adsorbed molecule will be stretched, an action which must play a part in catalysis.2 Recent experiments3 of Beebe, Taylor and others on "differential" heats of adsorption show that when some gases are adsorbed on certain surfaces, less -heat is evolved for the first portions of gas adsorbed than for later portions, indicating that the heat of adsorption is not the only factor