258 



lake the mean values for the twenty days previous to the date of 

 maturity we obtain the data in the second, third, and fourth columns, 

 and we notice that although in the warmer seasons there may be a 

 great variety in the value of the crop, yet in the cold seasons, 1877 

 and 1879, when the mean temperatures fell below the. limit (12.5°) 

 required for ripening, the crop was very poor or failed altogether. 

 If noAv the total radiation from sun and sky is computed according- 

 to Marie-Davy's method for the period betAveen leafing and flowering 

 and again from flowering to maturity Ave obtain the figures in the 

 columns five, six. and seven. Here we see, as before, that the variation 

 during the flowering period Avas of little importance, Avhereas that 

 during the ripening period has a direct relation to the character of 

 the wine crop, such that in general the larger the total radiation the 

 better the crop, provided the temperature of the air has not fallen 

 too low. 



In general, Marie-DaA-y concludes that the number of grapes to the 

 bunch and the number of bunches to the vine do not seem to have any 

 clear relation to meteorological conditions, except in the case of spring 

 frosts, Avhich can destroy a crop. Besides the conditions as to pruning 

 the vine and dressing the soil, the number of grapes that haA^e set (on 

 which principally depends the quantity of the tn-op that Avill be pro- 

 duced) is a result primarily of the meteorological conditions during 

 the previous year and of the state of preparation of the Avoody stock. 

 On the contrary the final size of the grapes and the quality of the 

 juice depends on the meteorological conditions of the crop year and 

 those that accompany the flowering and succeed it up to the time of 

 maturity. A final sum total of radiation is not ■ sufficient ; it is 

 necessary to take account of its distribution Avith reference to the 



