These pulsations are not continuous vibrations like the radiations of the spectrum; they are isolated and extremely short; they are, besides, transverse, like the undulations of light, and the theory shows that they must be propagated with the speed of light.

They should present neither refraction nor reflection, but, under certain conditions, they may be subject to the phenomena of diffraction.

All these characteristics are found in the Roentgen rays.
Professor J.J.Thomson adopts an analogous idea, and states the precise way in which the pulsations may be produced at the moment when the electrified particles forming the cathode rays suddenly strike the anticathode wall.

The electromagnetic induction behaves in such a way that the magnetic field is not annihilated when the particle stops, and the new field produced, which is no longer in equilibrium, is propagated in the dielectric like an electric pulsation.

The electric and magnetic pulsations excited by this mechanism may give birth to effects similar to those of light.