the Occurrence of Enhanced Lines in the Arc. 301 



Wave- 

 lengths 



Ordinary arc 



Water arc 



Blown arc 





in air between 



between 



between 





Carbon cathode 



Carbon cathode 



Graphite anode 





in 



and 



and 



and 





I. A. 



Lead anode. 



Lead anode. 



Lead cathode. 





3683 5 



10 crb rv 



o cr, b 1 % ml 



5 cr, b rv in I 





37400 



10 c 



J5brvinl 

 i 3 in II 



6 c 





' 40196 



10 c 



f 10 in I 

 1 4 in II 



10 c 





! 4057-8 



20 crb rv 



30 cr, b ry in I 



30cr,b rv inl 





; 4062-2 



4c 



4c 



5c 





4168-0 



8c 



f 8 in I 

 { 4 in II 



8c 





42426 







JOinl 

 1 000 in II 



1 dd n 



enh, 



4245-2 







f 8 in I 



1 3 in II 



f6inl 



1 1 in II 



enh. 



4340-6 



4c 



00 cnn 



2 en 





4386-9 







J 8 in I 

 1 3 in II 



J 6 in I 

 I ! in II 



enh. 



: 5005 4 



12 c 



f 8 in I 

 1 4 in II 



8c 





; 5043-0 







J 2nninl 

 \ 000 in II 



1 dd mi 



enh. 



5201-4 



10 c 



/ 5 in I 



[ 2 in II 



4c 





: 5372-5 







3ddn 



2 dd n 



enh. 



i 5544-8 







Hddn 



1 dd n 



enh. 



, 5608-9 







" 8d 



8dn 



enh. 



5876-4 







00 dd 







enh. 



i 6002-0 



4c 



£cb r 



4c 





6011 



2c 







l^cn 





6059-9 



2c 



Ocn 



1 en 





6109 



2 u 







Ocn 





6234 



lc 



, 



i en 





6660-0 







4d 



4 dd n 



enh. 



6790 







|dd 



00 dd 



enh. 



II. Arc spectra of Tin, 



a. Quartz spectrograph. 



\X 2531 Strong in direct arc 1 , • -,, , , ,. , 



or-g ° I practically absent rrom water 



2632 Fairly strong in direct arc J 



3284 Absent from direct arc 1 , • , 



00-9 > very strong in water arc. 



4586 ,, „ ,, ., ; well marked in water arc. 



b. Reversals. 



The following lines are distinctly reversed in the direct 

 arc but not in the water arc nor in spark : AX 2200, 2210, 

 224,6, 2269, 2287, 2317, 2335, 2355, 2422, 2430, 2707 and 



