"N" Rays/Complementary Notes
(1) As mentioned in the Preliminary Notice and as will be seen in the later communications, the properties attributed in the present paper to "X" rays, belong not to these rays, but to a new kind of rays, to which I have given the name of "N" rays. The experiments are correct, and the rectification only applies to the nature of the rays which have been studied.
(2) What I attributed then to "S" rays is, in reality, due to diffused "N" rays. The rotation of the plane of polarization of "N" rays by active substances is perhaps very great, since their wave-lengths are very small. It may be, then, that the angles I have observed are merely the remainders obtained by subtracting 360° once or several times from the real rotations. For the same reason, the rotations in a contrary direction could be apparent only. Investigation on this point remains still to be carried out; the operations should be conducted successively on each of the homogeneous pencils resulting from the dispersion of a pencil of "N" rays by an aluminium prism. The existence of magnetic rotatory polarization has recently been shown by M. H. Bagard, whose investigations are still in progress. (C. R. t. cxxxviii.)
(3) Unpolished mica arrests a pencil of "N" rays; these are not, however, absorbed, but only diffused, as in the case of light.
(4) Rock-salt is in reality transparent. What had at first misled me was that the plate of salt I used, having been sawn out of a large block, had remained unpolished. In this state it was only translucent, whether for "N" rays or for light. When polished with wet paper, it becomes transparent both for "N" rays and light; when the polish disappears, it becomes translucent again.
(5) As I state in the text, these rough data on the transparency of different substances will have to be completed by new experiments methodically conducted. I have since found that copper continues to transmit "N" rays emitted by a Nernst lamp, even when used in thicknesses of 65 cms.; that, similarly, glass is very transparent, etc. M. Bichat has studied the transparency of various bodies; in particular, he has ascertained that the opacity of a sheet of lead is due to the fact that it is superficially covered with oxide and carbonate. Metallic lead lets pass certain of the "N" radiations. (See C. R. t. cxxxviii. p. 548, February 29, 1904.)
(6) See the communications of May 25 and June 15, 1903.
(7) I have since found that, on the contrary, "N" rays have much shorter wave-lengths than those of light. (See my communication of January 18, 1904 (p. 53 of the present volume).)
(8) See note above (7).
(9) The phosphorescence may be intense, provided it be not at its maximum.
(10) The piece of gold must of course be also receiving the "N" rays.
(11) These researches have since been communicated to the Academy of Sciences. (See C. R. t. cxxxvii. p. 1049, December 24, 1903.)
(12) According to some experiments which I have made with an aluminium lens on rays issuing from a knife-blade, these should have very large indices. M. Charpentier has found that wet cardboard transmits these rays. These questions remain to be studied.