HELIUM SERIES 



3889 447Z 



Pig. 3. — Spectrum of Helium, showing arrangement in Ser 



HELIUM 



(il) UNCONDENS[;0 DISCHARGE 



Fig. 5.— Spectrum of Heli 



4686 



(i) C0MDEN5ED DISCHAR&E. 

 Tube, with and without Coudeuser. 



