Classicly

The rapid advance of our knowledge of radio-activity has been dependent on the information already gained by research into the electric properties of gases. The action possessed by the radiations from radio-active bodies of producing charged carriers or ions in the gas, has formed the basis of an accurate quantitative method of examination of the properties of the radiations and of viiiradio-active processes, and also allows us to determine with considerable certainty the order of magnitude of the different quantities involved.