Radio-Activity

=254. Theories of radio-activity.= In previous chapters, a detailed account has been given of the nature and properties of the radiations, and of the complex processes taking pl...

matter is undergoing change accompanied by the expulsion of charged particles. It does not, however, by any means follow that because the atom of one element in the course of ti...

=138. Introduction.= A most important and striking property possessed by radium, thorium, and actinium, but not by uranium or polonium, is the power of continuously emitting int...

=25. Ionization of gases by radiation.= The most important property possessed by the radiations from radio-active bodies is their power of discharging bodies whether positively...

of the radium emanation, is due to a thin film of active matter deposited on the surface of bodies. This active deposit is a product of the decomposition of the radium emanation...

=1. Introduction.= The close of the old and the beginning of the new century have been marked by a very rapid increase of our knowledge of that most important but comparatively...

=273. Radio-activity of the atmosphere.= The experiments of Geitel[384] and C. T. R. Wilson[385] in 1900 showed that a positively or negatively charged conductor placed inside a...

=75. Discovery of the β rays.= A discovery which gave a great impetus to the study of the radiations from active bodies was made in 1899, almost simultaneously in Germany, Franc...

The photographic method has been used very widely, especially in the earlier development of the subject, but has gradually been displaced by the electrical method, as a quantita...

=205.= In the last chapter the mathematical theory of successive changes has been considered. The results there obtained will now be applied to explain the radio-active phenomen...

=243.= It was early recognised that a considerable amount of energy is emitted by the radio-active bodies in the form of their characteristic radiations. Most of the early estim...

=126.= An account will now be given of some experiments which have thrown much light, not only on the nature of the processes which serve to maintain the radio-activity of the r...

=115.= Besides their power of acting on a photographic plate, and of ionizing gases, the radiations from active bodies are able to produce marked chemical and physical actions i...

=193. Introduction.= We have seen in previous chapters that the radio-activity of the radio-elements is always accompanied by the production of a series of new substances with s...

=96. Experiments with a zinc sulphide screen.= A screen of Sidot’s hexagonal blend (phosphorescent crystalline zinc sulphide) lights up brightly under the action of the α rays o...

=87. The α rays=. The magnetic deviation of the β rays was discovered towards the end of 1899, at a comparatively early stage in the history of radio-activity, but three years e...

=184. The excited activity from actinium.= The emanation of actinium, like that of thorium and radium, produces excited activity on bodies, which is concentrated on the negative...

=175. Excited radio-activity.= One of the most interesting and remarkable properties of thorium, radium, and actinium, is their power of “exciting” or “inducing” temporary activ...

=113. Comparison of the ionization produced by the α and β rays=. With unscreened active material the ionization produced between two parallel plates, placed as in Fig. 17, is m...

=105.= In addition to the α and β rays, the three active substances, uranium, thorium, and radium, all give out a radiation of an extraordinarily penetrating character. These γ...

=109. Production of secondary rays.= It has long been known that Röntgen rays, when they impinge on solid obstacles, produce secondary rays of much less penetrating power than t...

=71. The Three Types of Radiation.= All the radio-active substances possess in common the power of acting on a photographic plate and of ionizing the gas in their immediate neig...

=215. Radio-activity of radium.= Notwithstanding the enormous difference in their relative activities, the radio-activity of radium presents many close analogies to that of thor...

“Mr Glazebrook’s volumes on Heat and Light deal with these subjects from the experimental side and it is difficult to admire sufficiently the ingenuity and simplicity of many of...

This nomenclature has arisen from the similarity of the shape of the current-voltage curves to the magnetization curves for iron. Since, on the ionization theory, the maximum cu...