On the radioactivity of summer clouds on Mount Olympus

Summary The radioactivity in different parts of a cloud as well as the radioactivity of the atmosphere before and after the cloud's passage are examined with stationary samplers — fall-out pans, Grunow cloud-catchers of various materials, and air-pumps — at elevations of 1800 m and 2817 m, on Mt Olympus — Greece. The relation between the cloud's density and its radioactivity is also examined.