Page:On a Complete Apparatus for the Study of the Properties of Electric Waves.djvu/1

Rh It will be noticed that in the case of the third mixture of the density and thermal expansion series (the same mixture) the differences are comparatively large, but it is obvious from the data of the fourth column in these series that the ionization-coefficients have not been accurately determined for mixtures of about the concentration of the one referred to. With these exceptions the agreement between observed and calculated values is satisfactory, the differences being either well within or at worst on the limit of observational error, up to mean concentrations of about 1·5. The determination of the ionization-coefficients was especially difficult in the case of the surface-tension observations, because Rother mixed equal weights of his simple solutions, not equal volumes. Nevertheless, in all except the strongest of these mixtures, the differences are probably not beyond the limits of experimental error. Obviously, alternation of sign is not to be expected in these calculations.

 IX. ''On a complete Apparatus for the Study of the Properties of Electric Waves. By, M.A. (Cantab.), D.Sc. (Lond.), Professor of Physical Science, Presidency College, Calcutta''.

HE work of Hertz and his eminent successors, both here and on the Continent, has opened out for study a new region of æthereal vibration, bridging over the gap that hitherto existed between the comparatively slow æther vibrations and the quick oscillations which give rise to radiant heat. In the vast range of possible æther vibrations we recognize only a few octaves by our senses; the rest are beyond our perception. Many unexpected properties of 