504 T. Mizuno on Tinfoil Grating as a 



(1) With the grating No. 1. 



Experiment. 



Initial 



Resistance. 



Final 

 Resistance. 



Decrease 

 of Resistance. 



1. 



132-4 



125-0 



74 -L 



2. 



132-2 



125-5 



6-7 || 



3. 



132-4 



125-2 



72 -J- 



4. 



132-4 



126-4 



6-0 || 



5. 



132-5 



1255 



7-0 J- 



6. 



132-7 



126-5 



6-2 || 



(2) With the 



grating No. 2. 







Experiment. 



Initial 

 Resistance. 



Final 



Resistance. 



Decrease 

 of Resistance. 



1. 



232-0 



189-9 



421 -i- 



2. 



232-0 



193-0 



39-0 || 



3. 



232-0 



187-0 



450 -L- 



4. 



232-0 



I960 



36-0 || 



5. 



232-4 



183-2 



49-2 -L 



6. 



232-2 



194-5 



37-7 || 



The signs in the last column indicate the direction of the 

 tinfoil strips of the gratings with respect to that of the 

 primary oscillations. Thus, the answer may be taken as 

 positive. 



Experiment 12. 



Lastly, I performed some experiments to decide the question 

 whether the change of resistance under consideration is a 

 molecular change as in a selenium cell or simply a mechanical 

 oiio. For this purpose I prepared very carefully another tin- 

 foil grating with a much wider space between the strips. It 

 was rectangular, 7 centim. in length and 6 centim. in breadth, 

 the total number of fine strips being 51. (See the figure.) 



The resistance of the grating thus prepared was 209 ohms. 



