PHYSICS 603 



La garde has measured, by means of the spectrophotometer of Crova, 

 the intensity of the hydrogen spectrum lines under various conditions 

 of temperature and pressure. Using the carcel lamp as a standard, 

 and calling the intensity of the corresponding regions of the spectrum 

 1,000. the intensity of the red line was 3.G under a pressure of 6 mm .5, 

 8.8 under a pressure of mm .542, and 12.6 under a pressure of mm .010, 

 the current intensity being the same. The blue line had an intensity 

 of 5.5, 25.8, and MO. 3 under these conditions, and the violet line 17.2, 

 05.8, and 110.0. For a pressure of 6 mm .5 the curve of the red line 

 becomes a straight line. (G. R.. December, 1882, xov, 1350; Phil. 

 Mag., March, 1883, V, xv, 220.) 



Liveiug and Dewar have presented to the Eoyal Society a paper on 

 the origin of the hydrocarbon flame spectrum. (Nature, January, 1883, 

 xxvn, 257.) 



Thaleu has measured the wave-lengths of the brilliant spectra of 

 samarium and didymium. (J. Phys., October, 1883, II, n, 446.) 



The same physicist has mapped the emission spectra of scandium, 

 ytterbium, and thulium, as well as the absorption spectrum of thulium. 

 (J. Phys., January, 1883, II, n, 35.) 



Cornu has compared together the telluric lines of the spectrum and 

 the liues of the metals as a means of determining the absorbing power 

 of the atmosphere. (J. Phys., February, 1883, II, n, 58.) 



Liveing and Dewar have studied the conditions under which the 

 spectrum lines of the metals are reversed. (J. Phys., September, 1883, 

 II, ii, 434.) 



Hartley has submitted to the British Association the report of the 

 committee on the comparison of the spark spectra of the elements with 

 spectra of solutions of their compounds. (Nature, November, 1883, 

 xxix, 89.) 



Abney has communicated to the Eoyal Society the results of his 

 measurements of the wavelengths of A, of a, and of some prominent 

 lines in the infra-red of the visible spectrum. (Nature, December, 1883, 

 xxix, 190.) 



Pringsheim has measured the ultra-red wave-lengths of the solar 

 spectrum, using a Chapman grating and silvered mirrors, the rays being 

 received on an extra sensitive radiometer. The visible spectrum of the 

 second order was absorbed by a solution of iodine or a plate of ebonite. 

 He concludes that rays exist in the spectrum of wave-length 0.00152, 

 or double the length of the extreme red. He finds a cold band between 

 the limits /l=0.00139 and ;>=0.001366. This band has also been observed 

 by Langley. ( Wied. Ann., xvm, 32 ; J. Phys., September, 1883, II, n, 

 424.) 



H. Becquerel has published three papers on the infra-red region of 

 the spectrum. The first is on a phosphorograph of the infra-red region 

 of the solar spectrum and the wave-length of the piincipal lines. The 

 second is on the study of the infra-red radiation by means of the phe- 



