-""'••f7';Tr7" i 'y?7~'"'*"rrTT?7 



II3S ' 



i I 1 1 1 1 1 1 1 1 1 I I I I I I L_ 



_1 I I U 



- « 



• ae 



ti I* n St •> «• tS M •> U TS T« » ■■ as •• I 



■ 0« 11) III It) m I)) ■)• hi) Ml IS) IB* M 



MARGINAL INCREMENT , MM 



Figure 4* Rrequencies of marginal increment widths in scales having 

 0, 1, and 2 rings. Dimensions are in millimeters of projected image; 

 magnification is 431 diameters. The 32,5 mm, point is arbitrarily 

 chosen as separating the narrcvr from the vide increments* 



67 



