A STUDY OF VARIATION IN APPLES. 



31 



sixteenth day seems to fit the observed fluctuations in form better than 

 that for any other period. The relationship of the temperature for this 

 period and the coefficient of form are as follows, the arrangement being 

 in the order of the increase of temperature : — 



Year. 



Date of Full Bloom. 



Temperature, 



Sixth 

 to Sixteenth 



Day. 



Coefficient 

 of Form. 



1913, 

 1910, 

 1909, 

 1912, 

 1908, 

 1911, 



May 7, 

 May 7, 

 May 19, 

 May 11, 

 May 19, 

 May 15, 



51.24 

 54.44 

 58.19 

 62.10 

 67.63 

 67.76 



1.1192 

 1.1238 

 1.1338 

 1 1536 

 1.1515 

 1.1579 



An inspection of these figures shows the general relationship, but there 

 are some irregularities, especially in 1912 and 1908. In the latter year 

 this period was slightly over 5° warmer than in 1912, yet the apples were 

 more elongated. Tree No. 8 was not measured in 1908, but its apples 

 have only once been more flattened than the average and then only 

 shghtly so. The difference between extremes of temperature for this 

 period is 16.52° (67.76°-51.24°), and in the coefficient of form, .0387 

 (1.1579-1.1192). This gives an average difference of .0022 for each 

 degree of temperature. If we calculate the relationship of the increase 

 of the coefficient of form with that of temperature from year to year we 

 get the following : — 



Looked at from this viewpoint the only very serious difference between 

 the actual and theoretical increases of the coefficient of form with the rise 

 of temperature is in 1912, when it is 1.1536, whereas it should be, in order 

 to be in harmony with other years, 1.1430. We have endeavored to ac- 

 count for this irregularity, but without success. Presumably some un- 

 known factor operated to disturb the fairly close relationship observed 

 in other years. Probably it will be necessary to attack the problem from 

 another angle in order to understand what this may be. 



