The mechanism whereby neutral carbon monoxide is ejected from the ($-OH)+ ion from o-nitrotoluene under electron impact has been studied. The compound o-nitro[Me-13C] toluene was prepared in order to assist this study.

Vol. 65 tion and dependent, in the case of the alcohol, on steric hindrance. While the alcohol oriented polar end down, both in physical and chemical adsorption, the chloride did not. This compound was predominantly physically adsorbed and oriented flat-wise with the very large C.S.A. of 46.2 Obviously, the assumptions made by the workers utilizing single heat measurements are unsound.Many more criticisms could be leveled. Unfortunately, it appears that the practice of drawing conclusions from heat of immersional values of clean samples originated with Harkins and has persisted too long. For example, Harkins18 con-( 16) W. D. Harkins, "The Physical Chemistry of Surface Films,"