On a Certain Class of Fraunhofer' s 

 Diffraction-Phenomena. 



By 



H. Nagaoka, Rièakuhakushi. 



The intensity of light for Fraunhofers diifraction-phenomena is 

 proportional to 7, where 



I = C 2 + tf , 



C and S being put for the surface-integrals 



C =-- J fdxdy cos -j- (x (a - a ) + y (ß - ß ) J 



S=f fdxdy sin-^f-(x(a-a )+y(ß-ß )) 



In the above expression, ^ denotes the wave-length of light; 

 «, ß cosines of the angles made by the incident ray with the axes 

 of x and y resp., « » ß those for the diffracted ray; the coordinate 

 axes lie in the plane of the diffracting opening, over which the 

 integration is to extend. 



Putting 



—j- (« - a o) = !>■ , -j- (ß-ßo) = » > 



we can write 



1= \ffe i{fMX+vy) dxd y y. 



For n openings of the same size similarly situated, the expression 

 for 7 is greatly simplified by means of Bridge's theorem. Denoting 



