Size and Vertical Distributions of Stratospheric Radioactive Aerosols . P. J. Drevinsky and J. Pecei Fallout Measurements by Total-absorption Gamma- 158 ray Spectroscopy . 183 Measurements of Airborne Radionuclides and Determinations of Their Physical Characteristics . 198 Robert S. Foote R. W. Perkins, C. W. Thomas, and J. M. Nielsen Measurements of the Particle Size Distribution of the Tropospheric Aerosol with the Rotating-disk Sampler. . . S. K, Friedlander and Ralph E. Pasceri_ 222 Dosimetric Investigations of Environmental Gamma Radiation from Deposited Fission Products . 233 Wayne M. Lowder, Harold L. Beck, and William J. Condon 245 Session I Discussion. Se Long-term Particle Behavior 5. K. Friedlander, Chairman Theory of Self-preserving Size Distributions in a Coagulating Dispersion . 253 Particle Charging at Low Pressures oo 260 Kinetics of Wetting in Washout of Dust. . 281 S. K. Friedlander Benjamin Y. H. Liu and Kenneth T. Whitby T. G. Owe Berg, T. A. Gaukler, and LaVon A, Squier . Stratospheric Distribution of Nuclear Debris in 1962, 1963, and 1964, 301 Herbert W. Feely and Fernando Bazan 323 Session II Discussion Sa Local Atmospheric Transport Alfred W. Klement, Jr., Chairman Prediction of Fallout from Subsurface Nuclear Detonations. 331 Session IIA Discussion. 355 Joseph B. Knox Global Atmospheric Transport Elmar R. Reiter, Chairman Strontium-90 on the Earth’s Surface. TMI. . Robert J. List, Lester Machia, Lyle T. Alexander, James S, Allen, Milton W. Meyer, V. T. Valassis, and Edward P. Hardy, Jr. viii 359