THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



MA Y 1875. 



XXXVIII. On Spectra of Gases. By M. Eugen Goldstein*. 



"V^7ULLNER has recently published some experiments from 



* * which he concludes that the appearance of different 

 spectra of one and the same gas does not depend on the tem- 

 perature. 



It is known that the complete spectra of the gases have hitherto 

 only been produced by means of electrical discharges ; and we 

 are accustomed to distinguish two different kinds of discharges, 

 the continuous discharge and the disruptive discharge. 



Discharges which we call continuous show in a mirror rota- 

 ting about thirty times a second the image of a continuous field 

 of light. I will not decide whether this discharge is really con- 

 tinuous, or whether it consists of sparks following each other so 

 rapidly that the rotating mirror cannot resolve them into sepa- 

 rate images, at least not with the velocities which we can conve- 

 niently give to the mirror. This latter opinion, which Professor 

 Helmholtz considers to be the more probable one, is suggested 

 by the fact that just those means by which we can shorten the 

 time elapsing between the different discharges, lead at the end 

 to the so-called continuous discharge. The temperature is 

 doubtless the greater the more electricity passes in a single dis- 

 charge. It is therefore higher in discharges following each other 

 slowly than in the continuous discharge. The measurements 

 made by Riess with the electrical thermometer agree with this. 



According to Wiillner, the two forms of spectra which are 

 called by Pluck er and Hittorf spectra of the first and second 



* Communicated by Dr. Arthur Schuster, from Poggendorff's Annalen, 

 vol. cliv. pp. 128-149. 



Phil. Mag. S. 4. Vol. 49. No. 326. May 1875. 2 A 



