REFLECTED-LIGHT MICROSCOPY 



155 



Owing to the diamond's penetration, the surrounding surface is 

 distorted. Such distortions are those which are investigated by means 

 of interferometers. Figure 4.35 shows in the Zeiss interference mic- 



FiG. 4.35. Fringes brought about by the distortions surrounding the impression in micro- 

 hardness testing (Zeiss interference microscope. Von Martin Uhling; courtesy of Zeiss). 



roscope (photograph by Von Martin UhUng) the fringes brought about 

 by the distortions surrounding the impression. Figure 4.36 shows 

 the striking unsymmetrical impression obtained by Tolanslcy when 



