271 



table, there results an apparent continnation of our view tliat the 

 radiation during the flo>vering and ripeniiiii: phases has an important, 

 direct influence; in fact, the diminution of the average sunshine from 

 4,284 to 3,827 actinometric degrees has been accompanied by a 

 diminution of the crop from '2'k^^ to '20A hectoHters per hectare 

 This diminution of 25 per cent of the crop corresponds to a h)ss of 

 about 1.2 hectoliters per hectare, or 4 per cent of tlie normal crop, 

 for every 100 actinometric degrees. 



We have already seen that if we suppose the same number of stalks 

 to the hectare and the same relative total simi of solid nutriment 

 taken from the soil by each stalk, then, according to theory, the radia- 

 tion can serve as a measure of the possible work of assimilation by the 

 plant, and consequently of the actual sum total of the assimilated 

 material. These conditions are never completely realized for many 

 reasons, and one can not hope for an exact relation between the crop 

 and the radiation, but it is interesting to see that the above-reported 

 crops, both in detail and general averages, confirm the theory. 



Some of the minor departures from perfect agreement are ex- 

 plained by a detailed examination of the conditions during the suc- 

 cessive phases of germination, heading, flowering, and ripening 

 during the good years and the poor years. The following table gives 

 the average climatic conditions during the first three phases and 

 shows that as between the good and bad years there can have been 

 but slight average differences in the condition of the stalks and the 

 embryo seeds up to the beginning of the ripening stage, as far as it 

 depends on climatic conditions. 



Compurifson of cliinateK during five ijood and four poor yean 



Stage. 



Germiuating period: 



Duration days.. 



Freezing weather days.. 



Average minimum temperatures "C. 



Rainfall during the period millimeters.. 



Heading ijeriod: 



Duration • days.. 



Freezing weather days.. 



Average of the minimum temperatures °C.. 



A vert-ge temperature at the epoch of heading "C. 



Average rainfall at the epoch of heading millimeters.. 



Flowering period: 



Duration days . . 



Mean daily temperature at the epoch of flowering ° C. . 



Average rainfall at the epoch of flowering millimeters.. 



Average radiation during this period Actinometric- degrees. . 



Ripening period: 



Average radiation during this period Actiuometri<- degrees.. 



Good 

 yeai's. 



ll.fi 



- 4.66 

 9.4 



114 

 5.7 



- 1.7 

 10.1 

 14.8 



75 

 16.3 

 ii6.3 

 2,826 



1,45H 



'.t.O 



- a. 7 

 11.6 



113 

 6.1 



- 2.1 

 9.7 



22.1 



80 

 16.3 

 31.6 

 2,525 



