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BELL SYSTEM TECHNICAL JOURNAL 



of these components the vibration is all in the plane of poz, of the other 

 the vibration is all perpendicular to the plane of poz. 



Z-OPTIC AXIS 



Fig. 2.19 — The velocities of light in a uniaxial crystal 



A plot of the propagation velocities for all directions is a surface of two 

 sheets, one octant of which is shown in Fig. 2.19. One sheet is a sphere; 



