Part I. The Standard Entropies of Several Compounds. Part II. Theory of the Thermal Diffusion of Electrolytes in a Clusius Column. Part III. A Study of the Structure of Sulphur-Monochloride by Electron Diffraction. Part IV. A Study of Factors in the

The standard entropies of isopentane, ethyl benzene, azelaic acid and sebacic acid have been determined by the method of the third law of thermodynamics. An anomalous hysteresis in the heat capacity of isopentane reported by Aston et al. was not found. A transition was found in sebacic acid crystals and is discussed. A theory is presented which accounts approximately for the apparently anomalous difference, between the thermal diffusion coefficients of the ions of an electrolyte in the presence and in the absence of other electrolytes. The structure of sulfur monochloride has been redetermined by electron diffraction. The molecule was found to have an extended structure. The parameters have been determined and are reported. The theoretical expression for the scattering of electrons by gases is altered by a camera of finite dimensions. An approximate theory of the alteration in terms of the camera dimensions (and electron lens parameters) has been developed. An expression for the effect of multiple scattering has been obtained.