89activity of his "bonds" and of association as reducing them.The view that dissociation-association processes take place in glass is not at variance with the evidence of X-ray diffraction patterns. This evidence is confined almost entirely to giving distances and coordination numbers of ions adjacent to a given ion, e.g., 4 oxygens about a central silicon, and tells practically nothing about phenomena occurring two or more atoms distant. As shown by Warren in Morey's paper,l the X-ray pattern of a sample of Pyrex-brand glass after 731 days at 430°C was just a little sharper and more intense at large diffraction angles than that of the quenched sample. What evidence there is supports the idea that the randomness and distortion should be reduced, and the various interneighbor distances should fall somewhat closer to a series of definite values, as annealing progresses.Qualitatively, the ideas of association given in the present paper are already widely accepted. The particular contribution made here is a quantitative treatment to the whole annealing problem and, perhaps, a more intimate picture of the molecular nature of stress and strain.One test of the law of strain release as given here would consist in the measurement of the rate-of-strain release in a sample of stabilized glass. In this case, the dissociation-association processes have reached equilibrium and the Adams-Williamson law should not be obeyed, but only the Maxwell law.ABSTRACT A simple method is described for measuring the complete range of particle sizes in a clay, with equipment which can readily be used in the plant-control laboratory. The usual Casagrande sedimentation method is extended to lower limits of size by swinging the suspension in a long arm centrifuge by which means particles can be measured as small as 0.05 micron. Distribution curves are shown for several types of clay and the precision of the results are discussed.
