500 



T. Mizuno on Tinfoil Grating as a 



Experiment 4. 



Next, a grating, rectangular in form, 27 centim. in length 

 and 22 centim. in breadth, was made, the average distance 

 between two consecutive strips being about 0*6 centim. 

 Placing this grating in a vertical position in front of the 

 parabola and bringing the grating just behind it, the following 

 changes in resistance were observed : — 



Experiment. 



Initial 

 Resistance. 



Final 

 Resistance. 



Decrease 

 of Resistance. 



1. 



2. 

 3. 



129-7 

 1291 

 129-2 



123 7 

 124-1 

 123-5 



6-9 

 50 



5-7 



Experiment 5. 



Substituting for the above grating a large wire grating, 

 1*7 metre in the side and with consecutive wires 3 centim. 

 apart, I have found the changes of resistance as follows : — 



Experiment. 



Initial 

 Resistance. 



Final 

 Resistance. 



Decrease 

 of Resistance. 



1. 



129-9 



126-5 



3-4 || 



2. 



129-9 



123-4 



6-5 -1- 



3. 



129-9 



126-7 



3-2 || 



4. 



130-2 



124-5 



5-7 -L 



5. 



130-4 



1270 



3-4 || 



6. 



130-3 



1241 



6-2 J- 



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 polarized waves 

 on my tinfoil grating. The experiments have shown 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 shown a 



