18 



T. MIZUNO. 



vertical position in front of the parabola and bringing the grating just 

 behind it, the following changes in resistance were observed : 



Experiment 5. 



Substituting for the above grating a large wire grating, 1*7 m. in 

 the side and with consecutive wires 3 cm. apart, I have found the 

 changes of resistance as follows : — ■ 



The signs in the last column of the above table denote the 

 orientations of the wire grating according as the wires were placed 

 parallel or perpendicular to the primary vibrator. The results show 

 how different are the effects of polarised waves on my tinfoil grating. 

 The experiments have shewn also how sensitive the tinfoil grating is 

 to the action of electric waves in comparison with my rectilinear 

 tinfoil resonator, because I have found that whereas the former has 

 shewn a large amount of change in resistance the latter gave no per- 

 ceptible resonance spark. 



