198 EXPERIMENT STATION. [Jan. 1910. 



as Pennsylvania and possibly farther in the mountain regions, 

 and from the Pacific coast. 



3. The oblate or oblate conic type from the Delaware penin- 

 sula and the valley of the Ohio and its tributaries. 



4. The roundish oblate form from the Ozarks and from 

 Colorado. 



The outlines of specimens representing these four types are 

 shown in Fig. 2. Each of these types seems to be pretty con- 

 stant in the localities given, and they gradually shade into each 

 other in passing from one region to the next. These differences 

 in form are closely related with certain other characters which 

 are discussed later. 



Coming now to the mathematical expression of the form of the 

 apples, the method was as follows. Each apple was carefully 

 measured, ascertaining in millimeters its greatest transverse and 

 longitudinal diameters, and the figures recorded. Then the 

 transverse diameter of each apple was divided by its greatest lon- 

 gitudinal diameter. The number resulting from this calcula- 

 tion was taken as representing the form of the apple, and is 

 called the index or coefficient of form. If the index is 1 the 

 diameters are equal ; if it is less than 1 the apple is longer than 

 broad, and if more than 1 it is broader than long. The calcu- 

 lation of this index for a large number of apples gives an array 

 of numbers representing the forms of the apples measured 

 which may be dealt with by statistical methods.^ 



Calculating the means of the several arrays representing the 

 different lots of apples measured gives the interesting and sig- 

 nificant figures shown in Table 3. Translated into simple 

 language these figures mean that in Port Williams, N. S., for 

 example, the average Ben Davis apple of the crop of 1907 was 

 about 1.0196 larger in transverse diameter than in longitudinal 

 diameter, and, as shown by the probable error, the chances are 

 even that this figure is not over .0035 of the transverse diameter 

 away from the truth. This average apple is nearly as long as 

 broad, and to one familiar with this sort of measurement indi- 

 cates an apple that may be correctly described as oblong. 



• For these methods see C. B. Davenport, "Statistical Methods," or "Principles of Breeding," 

 by K. Davenport. v 



