XIX, 1. Rheinberg: Common Basis ofthe Theories ofMicroscopic Vision. 19 



consider not only the etfect (lue to each slot separately, biit the 

 effect dne to waves emanating from the one slot interfering- with 

 those emanating from the others. 



In figure 18 the wave front is curved, and we suppose our 

 slots to be sitnate on that cnrve. That is both inconvenient for 



X--Z 



18. 



19. 



experimental pnrposes and for diagrammatic explanations of what 

 occurs. By the simple expedient of bringing the point P nearer the 

 lens, we can cause the wave front to become a tlat or plane parallel 

 surface, and by using another lens we can bring all sets of parallel 

 rays back to one focus, as shown in figure 19. That greatly 



