308 SMITHSONIAN MISC£l,I.ANEOUS COLLECTIONS VOL. 52 



Magnitude of Maximum Magnetic Deflection. 



Maximum deflection about 2 cm. with field of 500 C. G. S. units, tension 

 30,000 v., screen at a distance of 7 cm. from cathode : 

 W4(43i) ; W5(s6i, 263) ; W8(663). 

 Originally reported deflection much smaller: W2(i2) ; W3(448). 

 Independent of gas and also of cathode material. In H2, however, a 

 larger proportion seem to be deflected nearly the maxi- 

 mum amount: W4(43i) ; W9(674) ; Tm3(575). 

 LoN'G Canal Ray Beam. Curious behavior in magnetic field: Pli(ioo8). 



7. ELECTROSTATIC DEFLECTION. 



Difficult to Observe because gas becomes ionized by the rays, and electric 

 field cannot be maintained: W2(ii) ; W3(447) ^ 



W4(42S). 

 Effect small; first observed by W. Wien in 1898: W2(io) ; W3(447). 



Sense of Deflection same as that of magnetic deflection: W2(ii), etc. 



Character. Same as that of magnetic deflection: WsCsdo, 259) ; Tm3(564). 



Magnitude. With a field of 400 v./cm., discharge potential of 10.000 v.,. 

 length of plates 5 cm., distance of screen 10 cm., a deflec- 

 tion of about I cm. would be obtained : Ws(56i, 259, 264). 



Electrostatic Acceleration of Rays. 



By applying a field parallel to the rays, the fluorescence can be weakened 

 or brightened according to direction of field: Ws(56i^ 

 260). 



8. SIMULTANEOUS MAGNETIC AND ELECTROSTATIC DEFLECTION. 



Experiment due to W. Wien: W5(56i, 261). 



Magnetic and electrostatic fields are superposed, and so arranged that 

 they tend to deflect the rays in mutually perpendicular 

 planes. The resultant deflection streak is observed on 

 the glass or willemite screen at the end of the tube. 

 With Ordinary Low Pressures. 



Fairly straight diagonal streak extending from origin, in air, H- or pure 

 0=: Ws(56i, 263) ; W6(588) ; W8 (661-3). For diagrams 

 see Tm3(568, 571). 

 With Extremely Low Pressures. 



Undeflected spot and negative branch disappear: Tm3(572). 

 Streak breaks up into two or three patches. 



Same hvo patches for all gases air, Hj. O-j, He, CO2, Ar, and Ne. 

 He giving, in addition, a third patch: Tm3(573. 575); 

 Tm6(295). 

 One patch is deflected the amount to be expected if canal rays are 



singly charged hydrogen atoms. 

 Second patch corresponds to singly charged hydrogen molecules. 

 Third patch, obtained under certain conditions with helium, cor- 

 responds to singly charged helium molecules: Tm3(57i). 



