156 



PROGRESS IN MICROSCOPY 



Fjg. 4.36. Unsymmetrical impression obtained by Tolansky when carrying out micro- 

 hardness tests on a tin mono-crystal (courtesy of Prof. Tolansky). 



Fig. 4.37. Fringes when a small steel diamond-chip wheel is applied against a surface 

 at a given pressure (courtesy of Prof. Tolansky). 



