474 Dr. Megh Nad Saha on Ionization 



to Rydberg, and m + a + ^[i(m)], according to Ritz, t(m) 

 being a function of m which vanishes with increasing values 

 of m. 



In other words, in the series formula of the enhanced 

 lines, the spectroscopic constant is 4N instead of the usual 

 Rydberg number N. In the light of Bohr's theory, this is 

 to be understood in the sense that, during the emission of 

 the enhanced lines, the nucleus, and the system of electrons 

 (excluding the vibrating one) taken together behave ap- 

 proximately as a double charge, so that the spectroscopic 



constant, = p — , becomes 4N, as E = 2*?. This means 



that if the nuclear charge is n, the total number of electrons 

 is (n—1), and the system has been produced by the removal 

 of one electron from the normal atom. 



What has been said of the Calcium lines H and K is also 

 true of the Strontium pair 4216 and 4078, and the Barium 

 pair 4934 and 4554, i. <?., they are due to the ionized atom 

 of these elements. The principal lines of the system of 

 single lines of these elements also occur in the flash spec- 

 trum, but the following table shows that they reach a much 

 lowpr level : — 



Table II. 



Lines clue to Chromo- Lines due to Chromo- 



the Ionized spheric the Normal spheric 



Element. Atom. level. Atom. level. 



Ca (1)3933} 14000 (.?) 422 ? 5000 



Sr 4^8 } 6000 4607 350 



Ba 49341 750 \ r . 



4554 \ 1200/ ■ ° 536 40 ° 



N.B. — The lines chosen are the fundamental lines or the first lines of 

 the principal series, having the symbolic formula v = {l . S) — (2 . P). 



No satisfactory series formula are known for the other 

 high-level ehromospheric elements, viz., Titanium, Scandium, 

 Iron, and other elements. But the recent remarkable work 

 of Kossel and Sommerfc'eld * makes it quite clear that the 

 spark -lines of these elements are due to the ionized atom. 

 The spark-lines of alkalies have not been much investigated 

 and lie in the ultraviolet beyond 3000, so that, even if they 



* Kossel and Sommerfeld, Ber. d. d. Phys. Gesellscliaft, Jahrgang 21, 

 p. 240. 



