Second Spectrum of Hydrogen. 



345 



whilst the measurements of the rest of the spectrum given in 

 Table B have been made by means of the tubes Nos. 2 and 4. 

 The employment of a higher magnifying-power with the 

 Series III. and IV. of Table A is the reason why single fine 

 lines occur in these Series which are absent in the Series I. 

 and II. All the values of Table B were obtained by employ- 

 ing the higher magnifying-power. 



As far as the general arrangement of the tables is concerned, 

 it is only necessary to remark that the wave-lengths are ex- 

 pressed in ten-millionths of a millimetre, and that the numbers 

 in column J give the estimated intensities of the lines ; the 

 numbers 1 to 6 being employed, 1 to denote the weakest 

 scarcely perceptible line, and 6 the strongest. Certain lines 

 having a somewhat hazy appearance are marked v. Lastly, 

 under V and S are given the somewhat older determinations 

 of Vogel and Seabroke, of which the latter have been reduced 

 from KirchhofFs scale to wave-lengths. 



Table A. 

 From \=6400 to \ = 5630. 















Older deter- 



Series 

 I. 



Series 

 II. 



Series 

 III. 



Series 

 IV. 



Mean. 



J. 



Eemarks. 



minations. 



V. 



s. 









6408-0 



6408-0 



1 1 



Very difficult to see. 









... 





6383-5 



6383-5 



1 



X in consequence 









... 





66-8 



6366-8 



1 J 



somewhat uncertain. 







6328-0 



6327-8 





30-4 



6328-7 



2 









023 



00-2 





02-4 



6301-6 



1—2 









,.. 







628(r5 



6286-5 



1 









6274-7 



6273-3 





740 



62-8 

 46-1 



6274-0 

 6262-8 

 6246-1 



2 



1 

 1 









34-8 



340 





36 3 



62350 



4 









22-9 



22-9 





23-4 



62231 



4 









6199-0 



6199-4 



6197-4 



6199-9 



6198-9 



5 



v. 







77-4 



80-2 



836 

 72-6 



84-5 

 756 



61814 

 61741 



2 

 3 









60-1 



60-2 



59-5 



62-6 



6160-6 



3 



Perhaps oxygen. 







32-9 



347 



34-0 



34-8 



6134-1 



5—6 



| There is a fine line 

 J between these lines. 





J6129 



19-3 



20-1 



18-6 



20-8 



6119-7 



4—5 





01-3 



01-7 



6097-3 



60996 

 90-5 



6100-1 

 6090*5 



2 



Boundary of a bright 

 region on which the 







6085-3 



60864 



79-8 



82-4 



6083-5 



3 



three following lines 







74-7 



73-1 



66-5 



691 

 63-9 



6072-3 

 6065-2 



4 



2 



arc placed. 







Phil. Mag. S. 5. Vol. 17. No. 107. May 1884. 2 A 



