those which graze the cathode. One should expect these to be very incompletely polarized; and, indeed the small spark enabled me to confirm this.
I noted several important facts, which, however, I will merely allude to in the present paper. Quartz and lump-sugar rotate the plane of polarization of "X" rays in the same sense as that of light. I obtained rotations of 40°.
Secondary rays, styled "S" rays, are also polarized. Active substances rotate the plane of polarization of these rays in a sense contrary to that of light. I observed rotations of 18° (note 2).
It is extremely likely that magnetic rotation also exists for "X" rays as well as for "S" rays. One can also surmise that the properties of these rays, with reference to polarization, extend to tertiary rays, etc. I intend shortly to publish the results at which I have arrived concerning these different points.