High altitude studies of ionizing radiation.

This thesis is primarily concerned with investigations of ionizing radiation in the atmosphere using balloon borne instruments. A programme of cosmic ray flights from Hobart was begun in 1959 under the direction of Dr. A.G.Fenton of the University Physics Department. I participated in the design, development, construction and successful flight of single geiger counter balloon sondes in partial fulfilment of the requirements for the degree of Bachelor of Science with honours which I received in 1960.