Early in 1964 the Hydro-University Computing Centre, a joint under taking by the University of Tasmania and the Tasmanian Hydro-Electric Commission, commenced operations with an Elliott 503 Digital Computer, This machine gave the Hobart Cosmic-Ray Group its first ready access to computing facilities, and it was immediately decided to develop computer programmes to carry out the various standard calculations. It would then be possible to undertake more precise analyses, and inter-station comparisons than had been feasible previously. This thesis is concerned with some of these investigations, into several aspects of the modulation of cosmic-rays, and with the development of the necessary computer programmes. Emphasis is given to the analysis of neutron monitor observations, but data from muon telescopes are also used where appropriate.