AbstractThe author has summarized the results of thirty years’research on the properties of powdered materials. These studies have been concerned with powders of all types, but most of the conclusions are applicable to metallic powders. The complex properties of powders can be resolved only by first defining those fundamental properties that can be measured individually; the first section of the paper defines these and shows how they may be combined to assess the more complex properties, according to the nature of the problem and the circumstances of usage. The second section describes the essential features of methods for the sizing analysis of powders, with brief consideration of their characteristics and some indication of recent tendencies in the application of electronic devices and automatic recording.