Chemistry and Physics. 381 



tunity for doublets. Only in the case of lithum exist simple 

 lines. The breadth of the doublets, that is the difference between 

 the powers of the position number n^ increase as the fourth 

 power of n. The number n = 'd m the case of sodium indicates 

 the yellow D lines. With Li the red line, with K, Rb red double 

 lines, and with Cs an ultra red double line, the higher values of 

 n = 4*5 etc. include the closely crowded together lines of the 

 ultra violet portion of the spectrum. Fkanz Kolacek has en- 

 deavored to find analogous series in the case of the electromag- 

 netic swinging of a conducting sphere, which is capable of 

 polarization, in a dielectrically polarizable ether. His mathe- 

 matical analysis conducts him to series which are analogous to 

 those treated by Kayser and Runge. — Ann. der Physik und 

 Chemie, No. 6, 1896, pp. 271-310. j. t. 



8. A Magnetic Detector of Electrical Waves. — E. Rutherfokd 

 states that the effect of Leyden jar discharges in partially demag- 

 netizing them affords a simple and convenient method of detect- 

 ing and comparing currents of great rapidity of alternation. The 

 partial demagnetization of a collection of fine steel wires, insulated 

 from each other, over which is wound a small solenoid in series 

 with the receiving wires, was found to be a sensitive means of 

 detecting electrical waves at long distances from the vibrator. A 

 small but quite marked effect was obtained at a distance of half 

 a mile from the vibrsitor.— Nature, July 9, 1896, p. 239. J. t. 



9. Discharge of an electrified body by means of the Tesla 

 Spark, — Frederick J. Smith states that a high frequency spark 

 between two blunt points one inch apart in air acts like the 

 Rontgen rays in dispelling electric charges, of either sign. — 

 Nature, July 30, p. 296. j. t. 



10. On the nature of the Rontgen rays ; by J. J. Thomson.* — 

 The discovery at the end of last year by Prof. Rontgen of a new 

 kind of radiation from a highly exhausted tube through which an 

 electric discharge is passing, has aroused an amount of interest 

 unprecedented in the history of physical science. The effects 

 produced inside such a tube by the kathode rays, the bright 

 phosphorescence of the glass, the shadows thrown by opaque 

 objects, the deffection of the rays by a magnet, have, thanks to 

 the researches of Crookes and Goldstein, long been familiar to us, 

 but it is only recently that the remarkable effects which occur 

 outside such a tube have been discovered. In 1893, Lenard, 

 using a tube provided with a window made of a very thin plate 

 of aluminium, found that a screen impregnated with a solution of 

 a phosphorescent substance became luminous if placed outside 

 the tube in the prolongation of the line from the kathode through 

 the aluminium window. He also found that photographic plates 

 placed outside the tube in this line were affected, and electrified 

 bodies were discharged ; he also obtained by these rays photo- 

 graphs through plates of aluminium or quartz. He found that 



* From an address delivered before Section A of the British Association at the 

 Liverpool meeting, Nature^ vol. liv, p. 47 2 et sec[. 



