ABS>Progress is reported in the following studies: the autoradiographic mapping of the deposition of Ca/sup 45/ in cortical bone in dogs; measurement of fission-product activity present in soil; factors affecting the performance of ionization chambers; calibration tests on the dibutyl phosphate method of isolating Th/sup 228/ from solutions of ashed bone; microradiographic demonstration of changes in mineral density in dog bones; radiometric determination of radon in bone and in the atmosphere; changes produced in xylene by exposure to massive doses of Co/sup 60/ gamma radiation; applications of the human spectrometer in in vivo measurements of Cs/sup 137/ build-up in humans; determinations of Cs/sup 137/ atmospheric content as a function of time; development of a tracer method using K/sup 42/ for measurement of exchangeable potassium in humans; determinations of the radium body burdens in fornner dial painters; and the atmospheric diffusion of stack particles. A meteorological model towing tank is described which was constructed as an alternative to a wind tunnel for model studies of atmospheric turbulent diffusion. Preliminary studies employing the apparatus are described. (For preceding period see ANL-5679.) (C.H.)

A list of publications and papers submitted for publication during the period is included. Progress is reported in the following studies: a decay-time study of an irradiated scintillating solution; the development of methods and equipment for use in measurements of the cosmic-ray neutron background; the effects of the addition of various gases singly and in pairs to the inert gas argon on results obtained with the halogen-sensitive positive ion tube used to measure the concentration of tracers in atmospheric air; the calibration of a quantitative alpha-track autoradiographic technique; studies on radiation carcinogenesis of radium and thorium oxides in the human skeleton; development of a method for counting individual alpha activities in mixtures in which the component activities do not show considerable variation; a survey of natural radium-226 and radium-228 content in municipal water supplies; radioac- . tivity measurements and dose calculations of soil collected at Argonne; the effect of various meteorological parameters on thermal conditions in the soil; design of an automatic data processing system which records data from nearly 200,000 meteorological measurements made annually; and studies on meteorological parameters affecting atmospheric diffusion of particles. (For preceding period see AN1.-5967.) (C.H.)