76 



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IVoiii 4700 A al 0,2 A. To some lines a dr is added to show (hat 

 thej are not surfieienll)' accurate. (Cf. Table 1). 



Argon can emit two types of spectra. One is the so-called i-ed 

 spectrnin, which is formed nnder the indnence of weak electi'ic 

 forces, and mnst, therefore, be called the arc-spectrnin of argon. 

 The other is forme(] by strong electric discharges, and is called the 

 bine S|)ectriim becanse of its colonr; it is the spark Sj)ect)Mim of 

 argon. No spectrum sei'ies are known in the red specti'um, but it 



o 



exhibits the regularity found by Rydbkkg') that for / <^ 4704 A 

 the (Vequencies of almost all the lines rjiay be arranged in a Table 

 the four columns of which present a constant diffeience. Paüi,son *) 

 extended these results to the less refrangible part of the spectrum. 

 Rvdbkrg's and Paulson's tables are reproduced hei-e in Table II, 

 somewhat abbreviated, but with continuous notation. It gives the 



o 



constant ditferences for the wave-lengths of A 9233—3319 A. (Cf. 

 Table II). The i-elations ai-e : 



B = A-i- 846,1 



C= A-\- 1649,3 



D = .4 + 2256,1 

 The frequencies in Table 11 followed by an M have been taken 

 from Mkggers'). They are more accui-ate than the frequencies in 

 the original tables of Rydberg and Paulson. For this reason the 

 mean value of Meggers has been put at the head of the Ar-column 

 and not the mean value of all Av's. 



The spark spectrum of potassium possesses the same property 

 Rydberg found in argon, for the examined region between 6594 — 



3063 A. This appears from Table 111, which has been obtained l)y 

 the aid of the data in Table 1. Under the heading "Remarks" in 

 Table I the lines inserted and arranged in Table 111 are indicated 

 by symbols (See Table 111). 



The relations for the lines of ionized potassium are: 



Q=P+ 847 



S = P-^ 2542 

 The first spark spectrum of potassium is, therefore, still somewhat 

 simpler than the red spectrum of aigon, the differences being: 



') Rydberg. On the constitution of the red spectrum of argon. Astroph. Journ. 

 Vol. 6. 338. 1897. 



2) Paulson, Bhysik. Z. S. 15. 831. 1914. 



3) Meggers, Scientific Papers, Bureau of Standards N". 414, 1918 



