266 Resonance of Metal Particles for JJijId- Waves. 



iire shown in the diagram. The plane of incidence is hori- 

 zontal in every case, i. e. the sheet o£ resonators stands vertical, 

 and at an angle of about 45 degrees with the incident light. 

 The direction of the electric vector is indicated by the double 

 arrow. In general the band drifts without much change in 

 intensity, though in some cases it fades away almost to the 

 vanishing point when the plane of polarization is at 45 degrees 

 to the plane of incidence. A case of this kind is shown in 



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the last three spectra of the figure. The band in this case 

 was crooked, as the slit of the spectroscope was placed at a 

 point where the colour of the film changed quite abruptly 

 from blue to purple. 



The appearance of several bands in the spectrum suggests 

 that we are dealing with something of the nature of multiple 

 resonance, and it is to be hoped that some of the mathematical 

 physicists will work out the behaviour of a sheet of small 

 spherical resonators at normal and oblique incidence for 

 vibrations polarized in different planes. 



