312 SMITHSONIAN MISCEU.ANEOUS COLLECTIONS VOL. 52 



In Hydrogen. 



Contains main series line spectrum: Win (132); SH(94)f4; 



85(894, 462) ; 89(112, 249). 

 Also X4688: 813(43, 425) ; 89(112, 249). 

 Also H band spectrum and sometimes metal lines: 8H(94)f4; 



85(461, 893) ; 813(43, 425)- 

 Line spectrum relatively more intense, the greater the discharge 



potential: SH(9S). 

 Intensity of shorter wave lengths increases faster: 810(253); 



821(799). Hence, as potential increases, the intensity 



maximum in the series shifts to shorter wave lengths: 



813(184, 444). 

 Doppler effect— see photo 85f i ; Ps2, plate HI ; 82of i ; SWff3 and 4. 



8hown by all lines of line spectrum: 85(462, 894); 813(33, 414); 



Hl2(i2); 01(589); PS2(250). 

 Cathode fall must exceed 700 v.: 820(64). 

 Rest line sharp, intensity less than that of displaced line : 



85(462, 894) ; 813(183, 443). Intensity closely related 



to that of band spectrum: 813(173, 43)- 

 Intensity of displaced line not a function of pressure: 8x3(34, 4i5) ', 



not related to stationary intensity: 813 ( 175, 434). 

 Ratio of intensities of displaced lines of different wave length in the 



same series is a function of the cathode fall: 88t(924). 

 Intensity distribution, or cross section of intensity is similar for all 



lines of series: Ps2(25o) ; Ps4(997) ; cf. 813(182, 442); 



821(799); 881(^924-5). For diagrams of intensity dis- 

 tribution see: HK(565) ; 8i3f5; Ps2(25o). 

 8hift as a function of wave length. 



AX/\ constant for maximum displacement of all lines showing 



effect: 85(462, 894) ; 89(112, 249) ; 813(33, 414)- 

 Constant for maximum intensity of displaced line: Ps2(25i) ; 



Ps4(997); cf. 821(799)- 

 Shift as a function of discharge potential. 8ee Fig. 61. 



Maximum shift proportional to the square root of potential 



approximately: 85(462). 

 8hift of about 5A for velocity of 3 x lo'cm. : Hl2(i2) ; 



813(33, 414)- 

 8hift the same for light from all parts of rays: 8W(745). 

 Second displaced line appears with low velocities, 800 to 2.000 v. : 

 Ps2(252 and plate iii). 

 Sharp for the lower velocities, widening for higher. 

 Band spectrum shows no Doppler effect: 85(463, 894) ; 813(43, 425)- 

 In Sodium Vapor. 



Difficulties of experiment: 88(457); 85(463)- Only one plate of a 



number, intense enough. 

 Contains main and first and second sub-series of line spectrum: 85(463)- 

 Doppler effect observed in case of two doublets of first series, a fine, 

 displaced line, shift not measurable: 88(460) ; 85(463). 



