283 



average 12.2° ; for the chestnut, 8° to 16° C, average 12.0° ; for the 

 elder, 9° to 20^ C, average 13.9° ; for the linden, 12° to 21° C, aver- 

 age 1().4°. The mean daily maximum temperatures at the date of 

 flowering for these same plants is as follows : 



Evidently the maximum temperatures have no clearer connection 

 with the date of flowering than have the mean daily temperatures. 



The sums of temperatures from the beginning of vegetation to the 

 date of flowering have also been computed by different methods and 

 from different initial temperatures. The following are the results 

 when the initial temperature is 0° C. : 



Here, again, as in previous cases, the relative value of the different 

 methods of taking account of the temperature is determined numer- 

 ically by taking the sums of the departures from the average for the 

 individual stations and years. In the present case the mean depart- 

 ures as thus determined are exactly the same for both methods, so 

 that four years of observations, 1880-1883, have not sufficed to decide 

 a.s to which mode of calculation it is proper to adopt lus the best. .V 

 similar calculation as to the amount of heat received by the lilac and 

 the chestnut between the epochs of leafing and flowering leads to the 

 same indecision as to the methods of calculation. The actual sums 

 between the leafing and the flowering are as follows : 



