The experiments to be described in this paper have been undertaken in order to obtain confirmation of the very interesting views put forward by Langmuir (1) upon the arrangement of the molecules of various substances spread upon the surface of water. The study of these films has been carried on by a number of workers for many years, some of the principal publications being those of Miss Pockels (2), Rayleigh (3, 4), Hardy (5), Devaux (6), and recently Labrouste (7) : but in most of these papers the authors do not enter into much detail regarding the molecular structure of the films. So much information is now available however as to the dimensions of molecules and the forces about them, much of it being of an accurate quantitative nature, derived from structural organic chemistry, from the study of crystals, the kinetic theory of gases and the deviations from the simple gas laws, etc., that an attempt to deduce the arrangement of the constituent molecules from the properties of the films has become something more than a speculation and may be made with some certainty and definiteness.
The properties and molecular structure of thin films of palmitic acid on water. Part I