240 



Temperature sums from January 1 to the date of first blossom {by Hoffmann's 

 method) at Oiessen and at Frankfort. 



[Z. O. G. M., Vol. X, 1875, p. 251, and Vol. XVI, p. 331. All in Reaumur degrees.] 



Lonicera alpigena 



Sambucus nigra — 



Berber is vulgaris 



Prunusavium 



Syringa vulgaris — 



Aesculus hippocastanum . 



Vitis vinifera - 



Prunus spinosa 



Giessen. 



ther-- 



mometer 



A. 



1,167 

 1,678 

 1,317 

 1,077 



1,317 

 2,600 



1,315 

 1,091 



1,091 

 1,069 

 1,995 



mometer mometer 

 Bi. Bo. 



Frank- 

 fort, 1875, 



ther- 

 mometer 



1,110 



Temperature sums {by Hoffmann's method) at Oiessen from January 1 to fir^t 

 blossom, for plants that blossom in midsummer and autumn. 



[Z. o. G. 



Vol. XVI, p. 331, and Vol. XVII, p. 130 ; M. Z., Vol. I, p. 407, and Vol. Ill, 

 p. 546.] 



The contrast between the ordinary spring of 1881 and the very 

 early spring of 1882 with its preceding warm winter, affords a test of 

 the question as to how much the thermal constant is liable to change 

 with the variations in the seasons. Hoifmann finds that although the 

 first blossoms in the spring of 1882 occurred fifteen days earlier than 

 usual, yet the sums of the maximum temperatures since January 1 

 ^ere not much changed. The figures as given by him (Z. O. G. M., 

 A'ol. XVII, p. 460) are reproduced as follows: 



Thermal sums. 



1882. 



Date of blossom- 

 ing. 



1881. 



Carpinus betulus 



Larix euroi)aea 



Lonicera alpigena 



Prunus spinosa. 



Ribes grossularia 



Crataegus oxyacantha 

 Sarothamnus vulgaris 

 Berbei-lH vulgaris 



1,159.7 

 789.9 

 1,471.7 

 1,159.7 

 1,086.5 

 1,681.6 

 1,790.8 

 1,681.6 



1,134.6 

 759.9 

 1,490.4 

 1,091.6 

 1,091.6 



1,751.9 

 1,751.9 



Apr. 19 

 Mar. 30 

 May 6 

 Apr. 19 

 Apr. 16 

 May 15 

 May 20 

 May 15 



Apr. 2 

 Mar. 15 

 Apr. 19 

 Mar. 31 

 Mar. 31 

 Apr. 30 

 May 1 

 May 1 



