ON THE DISPERSION OF "N" RAYS, AND ON THEIR ON THE PHOTOGRAPHIC REGISTERING OF THE ACTION ON A NEW SPECIES OF N RAYS ON PECULIARITIES PRESENTED BY THE ACTION WHICH "N" RAYS EXERCISE UPON A DIMLY LIGHTED SURFACE... ON THE COMPARATIVE ACTION OF HEAT AND N 19 INSTRUCTIONS FOR MAKING PHOSPHORESCENT SCREENS 53 "N" RAYS On the Polarization of "X" Rays (Feb. 2, 1903). Note I. HITHERTO the attempts made to polarize "X" rays have remained fruitless. I asked myself whether "X" rays emitted by a focus tube are not polarized as soon as emitted. I was led to put to myself this question by considering that the conditions of asymmetry which should exist for the polarization of such rays are in this case exactly satisfied. For each ray is generated from a cathode ray, and the two rays define a plane; thus, through each ray emitted by the tube a plane passes, in which, or normally to which, the ray may well have special properties, this being, in fact, an asymmetry characteristic of polarization. Now, if this polarization exists, how can the fact be ascertained? It struck me that a small spark, such B as I used in my researches on the velocity of propagation of "X" rays, might perhaps in this case play the part of analyzer, inasmuch as the properties of a spark may be different in the direction of its length, which is also that of the electric force producing it, and in directions normal to its length. Starting from this, I arranged an apparatus as shown in the accompanying diagram, so as to obtain a small spark during the emission of "X" rays. A focus tube is connected to an inductioncoil by wires BH, B'H', covered with guttapercha (Fig. 1). Two other wires, also covered with gutta-percha, AIc and A'Ic', terminate at A and A' in two loops, which surround BH and B'H' respectively; a bit of glass tubing, not shown in the figure, keeps each loop separate from the wire which it surrounds. The wires AI, A'I are then twisted together, and their sharply pointed ends, c and c', are fixed opposite each other, at a very small distance, adjustable at will, so as to form a small sparkgap. By virtue of this disposition, the electrostatic influence exercised by the wires BH and B'H' on the loops A and A' produces |