Chemistry and Physics. 337 



6. Spectrum of the oxyhydrogen flame. — Professors G. D. 

 Livehstg and J. Dewae find that the spectrum of water extends 

 with diminishing intensity, into the visible region on the one 

 hand and far into the ultra-violet on the other. The latter por- 

 tion they have photographed by means of a single calcite prism, 

 using a long exposure. " The spectrum exhibits the appearance 

 of a series of rhythmical groups more or less overlapping one an- 

 other, and the arrangement of the lines in these groups is shown 

 to follow, in many cases the law that the distances between the 

 lines, as measured, in wave-lengths, are in arithmetical progres- 

 sion." Their researches apparently confirm the theoretical con-., 

 elusions of Dr. Griinwald of Prague, for they discovered a num- 

 ber of lines which apparently occupy the positions which they 

 should according to his hypothesis. — Royal Society, Feb. 2 ; 

 Nature, Feb. 16, 1888, p. 383. j. t. 



7. Application of the Electrolysis of Copper to the Measure- 

 ment of Electric Currents. — In the process of standardizing Sir 

 William Thomson's new electrical instruments, Mr. Gbay has 

 been led to examine the accuracy of the method by means of the 

 deposition of copper, and concludes that the constant of an elec- 

 tric current instrument can be obtained with certainty, by this 

 method, to one-twentieth of one per cent.— Phil. Mag., March, 

 1888, p. 179. J. t. 



8. Influence of light upon electrical discharges, — Hertz in a 

 previous number of the Annalen der Physik having called atten- 

 tion to a remarkable influence of the ultra-violet rays upon elec- 

 trical discharges, E. Wiedemann and H. Ebert repeated his re- 

 searches and have confirmed his results. When a spark will no 

 longer pass between the terminals of a Ruhmkorff coil, if a beam 

 of ultra-violet light falls upon the electrodes the spark will 

 traverse the interval between the electrodes. Wiedemann and 

 Ebert show that the effect is also produced by the light of burn- 

 ing magnesium and that the effect is confined to the ultra-violet 

 i*ays; red and green producing no effect. The effect is produced 

 at the negative electrode and not at the positive. The authors 

 studied the effect in various gases, and at different pressures. The 

 phenomenon varied with the pressure and with the medium. 

 The same number of the Annalen contains a paper by W. Hall- 

 wachs on the influence of light upon electrostatically charged 

 bodies. He finds that the ultra-violet rays modify the charge and 

 the insulating properties of bodies. — Annalen der Physik und 

 Chemie, No. 2, 1888, pp. 241-264, 301-312. J. T. 



9. Wave-lengths of standard lines. — In a long paper continued 

 through two numbers of the Annalen der Physik, F. Ktjrlbaum 

 discusses the various methods of measurement of wave-length, and 

 gives the results of the most refined methods which his experience 

 has led him to adopt. His measures of the wave-length of one of 

 the components of the sodium line, D l5 compare as follows with 

 those of previous observers : 



