16 Mr. G. A. Hemsalech on the Relative Behaviour 



Of the quartet groups, a, 7, and 8 are the most interesting. 

 It will be noticed that the distances between their com- 

 ponents grow less on passing to groups of shorter wave- 

 lengths, the variations, as indicated by the A's, being 

 approximately as 1 : \ : \. Group /3 may possibly be con- 

 nected with the quartet group 4903 of the self-induction 

 spark (see below). In regard to the two triplets, it may be 

 mentioned that the distances between their components are 

 approximately as 2 : 1. 



Class II. Groups, 



Wave-length. 



f*3734-86cZ? 

 3749-47 

 3758-23 

 3763-80 



L 3767-19 



4271-75 cZ? 



4307-92 



4325-78 



Oscillation 

 Frequency. 



26774-8 

 26670-4 

 26608-3 

 26568-9 

 26545-0 



23409-6 

 23213-1 

 23117-2 



104-4 

 62-1 

 39-4 

 239 



196-5 

 95-9 



42-3 

 22-7 

 15-5 



In addition to the triplet here given, three more were found 

 in this class, among which were the two well-known triplets 

 at 4046 and 4384. Also here the ratio between the frequency 

 differences of successive components is approximately as 2 : 1. 

 The quintet at 3735 stands out most prominently in the 

 spectrum of the air- coal gas cone, but in the oxy-acetylene 

 flame it is quite insignificant as compared with the brilliancy 

 of the temperature lines in its neighbourhood (compare 

 Plate I. figs. 1 & 3). 



In all the groups of Classes I. and II. the head line is 

 on the most refrangible side, the groups converging towards 

 the red. 



Class III. Groups. 



Wave-length. 



Oscillation 

 Frequencj r . 



*!• 



A 2 . 



*T 



A 4 - 



f 4466-56 

 1 4476-03 



22388-6 



47-4 



92-1 



179-7 



3442 



013-9 









22341-2 



44-7 



42-9 

 76-9 



105-2 





j 4494-57 



22249-1 



87-6 



34-0 



1 4531-16 



22069-4 



164-5 



28-3 



1 4602-95 



21725-2 



269-7 





^ 4736-79 



21111-3 









f 485976 



20576-5 



48-2 



81-7 



117-3 



157-1 









| 4871-33 d? 



205^8-3 



33-5 



2-1 

 4-2 





<| 4890-78 d? 



20446-6 



35-6 





| 4919 01 d? 



203293 



39-8 





L*4957 31 d? 



20172-2 









