324 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. $2 



P. Lenard Ann. Phys. 17, 187. 



C. Fredenhagen Verb. Deutsch. Phys. Ges. 9, 393-401. 



C. Fredenhagen Phys. Zeitschr. 8, 72g-y2/, 927-9. 



G. Schott Phys. Zeitschr. 9, 214-216. 



G. Schott Phil. Mag. 15, 172-198. 



G. Schott Ann. Phys. 25, 63-91. 



J. Stark Phys. Zeitschr. 9, 85-94. 



3. CHEMICAL EFFECTS. 



No Direct Chemical Action of the rays other than that of splitting up the; 

 gas molecules, releasing their latent chemical activity. 

 Hence in O2 oxidation takes place, in H2 reduction: Sm2 (708-710) ; 

 Sm3(622); Sm4(ii3) ; S4(654) ; Ew3(304). 

 Disintegration. Double dependence on metal and gas indicates chemical 

 process, perhaps indirect. Not sensitive to traces of impurity : 

 Kli(872). 

 Fluorescence. 



(i) Explained as due to pressure of impact of rays: Tf 1(616); Tf2; 



Ew3(304). 

 (2) Explained as accompanying chemical reaction indirectly produced by 



the rays, varying with the gas: Sm2(7io). 

 Na light not the result of heating or oxidizing process: Raui(42i). 

 Solid solutions. Fluorescence explained 



(1) as accompanying reduction of higher oxides: W7. 



(2) as accompanying reduction of active compounds: Sm3(622). 



4. SECONDARY EMISSION OF CATHODE RAYS. 



Uniform Maximum Velocity explained by assuming electrons are merely 

 released by canal rays, being shot out by the atom with a definite velocity. 

 Distance penetrated by the rays determines how thick a layer the cathode 

 rays must pass through before emerging, hence determines the distribu- 

 tion of cathode rays of less velocity: F2(75o) ; F3(302). 



Increase of Intensity with Angle of Incidence is explained by assuming 

 canal rays do not penetrate so far, hence negative rays are not so much 

 absorbed in emerging. Effect is more marked with Al than Cu since 

 rays penetrate farther in the former: F3(3o6, 307). 



Negative rays may be created by ultra-violet light or Roentgen rays, but 

 probably not: F2(75o) ; F3(30i). 



Amherst College, Amherst, Mass., 

 November i, 1908. 



