259 



phenological perio is and of other accoiiip-uiying- circumstances. 

 Thus in 1877. with a low mean temperature and a high radiation 

 during maturity, and in 1879, with a low temperature and a low 

 radiation during the last phase, both alike gave a poor crop, but the 

 sunshine of l.'^77 was able to make a large quantity of sugar as 

 compared with the small quantity of sugar in 1871). 



Sugar heets. — Marie-Davy (1882) and Pagnoul (1870) give the 

 data of a research into the relation of climate to the development of 

 sugar beet as cultivated at Arras, the agricultural station of the 

 Department of Pas de Calais. The following table gives the i-esults 

 of meteorological observations and chemical analyses of sample beets 

 taken up every ten days during the season. The beets were sown 

 April 5, 1879, averaging six plants to the square meter. They were of 

 a poor variety, but of the kind ordinarily planted in that section ; 

 they were of a rosy color, and were planted a great distance apart in 

 order that they might grow more rapidly. 



Decade ending 

 1879. 



During the decade. 



Total 

 rain. 



Total 



heat 



(sum of 



mean 



daily 



shade 



tempera 



tures). 



Total 

 sunshine 



(daily 



average 



of clear 



skyj. 



Total 

 radia- 

 tion 

 (sum of 

 daily 

 actino- 

 metric 

 degrees 

 at Mont- 

 souris). 



At end of decade. 



Average 

 weight of— 



Root. Leaves. 



Aver- 

 age 

 density 



of 

 juice. 



Weight 



of sugar 



per 100 



beets. 



Weight 

 of sugar 



June 11 



June 21 



Julyl 



July 11 



July 21 



JulySl 



August 10 



August 20 



August 30 



September 9 . . 

 September 19 . 

 September 29 . 



October 9 



October 19 ... . 

 October 29 .... 



Per cent. 

 41 

 30 

 31 

 16 



Actin. 

 393 

 479 



Beau- 

 me. 



4.0 

 4.2 

 4.1 

 4.4 

 4.3 

 4.1 

 4.4 

 4.1 

 4.5 



2.13 



5.18 



.5.:w 



5.88 

 6.K5 



7.57 

 8.20 

 7.46 

 7.46 

 8.06 

 7.46 

 7.94 



■.m 



776 

 1,422 

 1,848 

 3,073 

 3,534 

 4,320 

 4,655 

 4,691 

 5,068 

 4,727 

 5,002 



The influence of sunshine is to be found by studying the fourth col- 

 umn of the sum total of daily average cloudiness at Arras, as result- 

 ing from twelve daily observations of the amount of cloudiness. The 

 clearness of the sky, as given in the fourth column in percentages, is 



