438 Intelligence and Miscellaneous Articles. 



observes that he has repeated the experiments with success • they 

 may be explained by assuming that the telephone which is sensitive 

 for a circuit is not so when the same quantity of electricity acts as 

 a feebly intermittent current. By experiments with intermittent 

 illumination and a rotating commutator it is proved that any 

 possible retardation of the action could not amount to yoVir of a 

 second. — Journal of the Russian Physicochemical Society, vol. xxi. 

 p. 159, 1889 ; Beibldtter der Physik, vol. xiv. p. 322. 



ON ACTINOELECTRIC PHENOMENA. BY J. BORGMANN. 



The net condenser of Stoltetow is illuminated by a rotating disk 

 with sectors cut out; the galvanometer is replaced by the tele- 

 phone. On closing the circuit a distinct shock is heard in the 

 telephone, but this is not the case with intermittent illumination. 

 The author concludes from this that the actinoelectrical discharge 

 is not instantaneous. — Ibid. 



STATIONARY LUMINOUS VIBRATIONS. BY O. WIENER. 



The author has published in Wiedemann's Annalen, vol. xl. p. 203, 

 an important Memoir, in which by photographic methods he has 

 demonstrated the existence of stationary luminous vibrations. The 

 memoir is accompanied by phototypic illustrations of the results 

 of his experiments. His conclusions are given by himself as 

 follows : — 



By the foregoing research the experimental proof has been fur- 

 nished for the existence of stationary waves of light. A sensitive, 

 perfectly transparent collodion lamina, the thickness of which was 

 small in comparison with the wave-length of light (-^ about) was 

 placed between two glass plates at a small distance from a metal 

 mirror and making a small angle with this. After protracted ex- 

 posure to the spectral rays the lamina was developed, and bands 

 were formed which it was proved could only be due to the action of 

 stationary waves. 



A more accurate investigation of stationary waves showed that 

 with perpendicular reflexion at the optically denser medium, the 

 nodal points of the chemical luminous action are at distances equal 

 to the multiple of half a wave-length from the reflecting surface ; 

 the ventral segments are between these, that is at distances equal 

 to the odd multiples of a quarter wave-length. 



Experiments in which two rectilinearly polarized waves of light 

 were used, which crossed each other at right angles, showed that a 

 chemical action on the sensitive plate due to an inference of the two 

 rays occurred when their planes of polarization coincided, but failed 

 when they were at right angles to each other. It was to be con- 

 cluded from this, that the chemically active vibrations of a recti- 

 linearly polarized wave of light are at right angles to their plane 

 of polarization. 



