CONTENTS. 



CHAPTER I. 

 ON METHODS OF MEASURING ORGANISMS. 



PAGE 



Preliminary definitions 1 



Methods of collecting individuals for measurement 2 



Processes preliminary to measuring characters 2 



The determination of integral variates Methods of counting 3 



The determination of graduated variates Method of measurement . 4 



Straight lines on a plane surface 4 



Distances through solid bodies or cavities 4 



Area of plane surfaces 4 



Area of a curved surface 5 



Characters occupying three dimensions of space 6 



Characters having weight 6 



Color characters 6 



Marking-characters 7 



Aids in calculating 7 



Precautions in arithmetical work 8 



CHAPTER II. 



ON THE SERIATION AND PLOTTING OF DATA AND THE FREQUENCY 

 POLYGON. 



Seriation 10 



Plotting 11 



Method of rectangles 11 



Method of loaded ordinates 12 



The rejection of extreme variates . . . 12 



Certain constants of the frequency polygon 13 



The average or mean ^ 13 



The mode 13 



The median magnitude 14 



The probable error of the determination 14 



The probable difference between two averages 15 , 



The probable error of the mean 15 



The probable error of the median 15 



The geometric mean 15 



The index of variability 15 



The probable error of the standard deviation 16 



Average deviation and probable departure 16 



V 



