Comparative Micrometric Measurements. By M. D. Ewell. 553 



series E. 



r = +1-2 div. 

 r = + • 4 div. 



Average deviation from mean 

 Greatest deviation from mean 



= + 0-015 p. 

 = + 0-005 /x 



= 1-3 div. = 0-02 fi. 

 = 3-5 div. = 0-04 p. 



SERIES F. 



= + 1 



= + 



div. = 

 3 div. = 



Average deviation from mean = 

 Greatest deviation from mean = 



± 0-01 fJL 



± 0-004 fi 



1-2 div. = 

 2-4 div. = 0' 



015 



03 p. 



fi. 



In order that the foregoing results may be more easily com- 

 pared, they are repeated in the following summary : — * 



* In the body of this paper the figures representing the probable errors, etc., 

 have usually been rounded off to the nearest 0-1 n or 0-Ol^t; they are, however, 

 for purposes of comparison merely, given at times to the third decimal place. 



Oct. 19th, 1910 2 P 



