514 



Dr. G. J. Stoney's Analysis of 



m. 



n calculated. 



k by observation 



(which is nearly the same 



as + n). 



Difference. 



1 



Used for determining the constants. 







2 



4- 86-966 



87-550 



-0'58 



3 



Used for detei 



■mining the constants. 







4 



+ 194-337 



194-120 



+022 



5 



4-210-662 



210-514 



+015 



6 



Used for determining the constants. 





7 



+225-919 



226-144 



-0-22 



8 



+229-816 



230-218 



-0-40 



Inferences. 



From the whole investigation we may draw the following 

 inferences : — 



1. That the outstanding differences are sufficiently large to 

 warrant the conclusion that the primary curve is not an exact 

 curve of the second degree, although in the case of Series P 

 it approximates to an hyperbola ; in the case of Series S to an 

 hyperbola or ellipse, probably to an hyperbola ; and to a para- 

 bola in the case of Series D. 



2. That the approach to the parabola is very close in the 

 case of Series D, but that in the case of Series P and in the 

 case of Series S the actual curve, as indicated by the observa- 

 tions, is somewhat more curved in the vicinity of its vertex 

 than is the hyperbola which approximates to it. 



3. That the double line which has been regarded by Bydberg 

 as a satellite of one of the terms of Series D, and by Kayser 

 and Eunge as belonging to a fourth series, is in reality the 

 first, or the second, term of Series S — the first, if the 

 primary curve of Series S is of a hyperbolic form ; the second 

 if it is elliptic. 



4. That negative values of n furnish real lines in spectra, of 

 which the double line spoken of above is an instance. 



5. That in Series P the term corresponding to m = l has a 

 negative value for its n, viz. — 469'4, approximately corre- 

 sponding to wave-length \ = 2130. This is perhaps not at 

 too great a distance in the ultra-violet to be observed, if the 

 line have sufficient intrinsic brightness. Professor Hartley 

 has succeeded in photographing as far as X=1800. 



