4 



Prof. J. N. Lockyer. 



[Nov. 21, 



II. ft On the New Gases obtained from Uraninite. (Sixth 

 Note.)" By J. Norman Lockyer, C.B., F.R.S. Received 

 September 10, 1895. 



As Mr. Crookes has now published* the wave-lengths of the lines 

 in the spectra of the new mineral gases observed by him in the tubes 

 supplied by Professor Ramsay, I propose in the present paper to 

 bring together some notes I have made (some of them some time ago) 

 on the same subject. 



The researches made at Kensington in connection with the new 

 gases obtained from broggerite and other minerals has consisted, to a 

 large extent, of comparisons of the lines in their spectra with lines 

 in the spectra of the sun and stars. Preliminary accounts of these 

 comparisons have already been given, and they show that the bright 

 yellow line seen in the gas from broggerite is by no means the only 

 important one which appears. 



Although the general distribution and intensities of the lines in 

 the gases from broggerite and cleveite sufficiently corresponded with 

 some of the chief " unknown lines " in the solar chromosphere and 

 some of the stars to render identity probable, it was desirable to see 

 how far the conclusion is sustained by detailed investigations of the 

 wave-lengths of the various lines. 



The Yelloiv Line X 5875*9. — Immediately on receiving from Professor 

 Ramsay, on March 28th, a small bulb of the gas obtained from 

 cleveite, a provisional determination of wave-length was made by 

 Mr. Fowler and myself, in the absence of the sun, by micrometric 

 comparisons with the D lines of sodium, the resulting wave-length 

 being 5876*07 on Rowland's scale. It was at once apparent, there- 

 fore, that the gas line was not far removed from the chromospheric 

 D 3 , the wave-length of which is given by Rowland as 5875*98. 



The bulb being too much blackened by sparking to give sufficient 

 luminosity for further measurements, I set about preparing some of 

 the gas for myself by heating broggerite in vacuo, in the manner I 

 have already described. A new measurement was thus secured on 

 March 30 with a spectroscope having a dense Jena* glass prism of 

 60° ; this gave the wave-length 5876'0. 



On April 5th, I attempted to make a direct comparison with the 

 chromospheric line, but though the lines were shown to be excessively 

 near to each other, the observations were not regarded as final. 



Professor Ramsay having been kind enough to furnish me, on 

 May 1, with a vacuum tube which showed the yellow line very 

 brilliantly, a further comparison with the chromosphere was made 



* « Chemical News,' August 23, 1895. 



