Abstract
THO deposition in the Southern Hemisphere is discussed in the light of currently available tritium measurements of Southern Hemisphere precipitation. Many new results from the New Zealand laboratory are presented. Topics discussed include the seasonal and latitudinal variations of THO fallout, the fallout history of tropospheric and stratospheric thermonuclear THO, and the effects of the continental environment upon many of the reported measurements. DOI: 10.1111/j.2153-3490.1966.tb01449.x