255 



The influence of the date of sowing and its relation to sunshine 

 and frost is fully shown in the table for Montsouris, which gives the 

 sum total of actinometric degrees from the time of germination to 

 maturity for seeds sown on successive weeks in 1879, 1880, and 1881, 

 and harvested in 1880, 1881, and 1882 : 



Date of sowing. 



Total sun- 

 shine fiMm 

 arerminatiiii: 



to ripening 

 (actinomet- 

 ric degrees) 



Total sun- 

 shine from 

 germination 

 to ripening 

 (actinomet- 

 ric degrees). 



1879 



October 1 



Octobers 



October 15 



October 22 



November 1 



Novembers 



November 15 



November 22 



1880, 



Februarys 



February 15 



February 23 



March 1 



September 29 c 



October 6c... 



October 13 



October 20d 



October 27d 



November 3<i 



November 10 



November 17 



November 24 



December 1 



December S_ 



December 15 



December 22 « 



December 29 e 



1881. 



January 5 



January 12 



January 19 



January 26 



February 2 



February 9 



February 16 



Februai-y 23 



March2 



March9 



Marchl6.. 



March 23 



March30. 



Apriia 



(/) 



,245 

 ,018 

 ,047 



a Frozen soil prevented sowing. 

 *>No sowing during this interval. 

 <• See note 1 in text. 



d See note 2 in text. 

 eSee note Sin text. 

 / Frozen ground prevented sowing. 



Among other conclusions that may be drawn from these figures are 

 the following, most of which are also given by Marie-Davy : 



1. The season 1880-81 was characterized by much sunshine and 

 little rain, which hastened the ripening, but delayed the flow of nap, 

 and therefore of nourishment to the grain, so that the crop was rather 

 poor. 



2. For the crops of fall wheat the sunshine increased more and more 

 as the seed was sown later from September, 1880, even to the end of 

 December; then it began to diminish, and for the spring wheat, sown 

 in March, 1881, it was too small. 



3. By considering other weather records it is evident that the 

 freezing of the ground in January, 1881, not only prevented the sow- 

 ing of the seed, as noted in our table, but prevented the germination 

 of the seeds sown on December 22 and 29, 1880, which would other- 

 wise have sprouted on February 4 and 19, 1881, respectively. 



