We recently spoke of the discovery of the remarkable N rays and commented on their sources. The properties of the rays have been determined sufficiently so that the rays may be properly classified. They are reflected from polished surfaces, such as glass, and are also refracted, as is shown by the fact that they can be focused by means of a quartz lens. It should be stated that several foci may be obtained in this way, indicating that there are rays of different wave lengths. The index of refraction was found by Blondlot to vary from 1.04 to 1.85. Wave-length determinations vary from 0.008 μ to 0.018 μ. They are, therefore, rays of very short wave lengths, and the above measurements place them in the spectrum far out beyond the ultraviolet. The rays can be polarized, differing essentially from x-rays.
The penetrability of these rays is remarkable. They pass through