257 



on the meteorological conclitioiis, but, equally or more, on the condi- 

 tion of the woody fiber of the stock and stems. Similarly the date of 

 flowering is calculated by assuming, with Gasparin, that the sum total 

 of the mean daily temperatures in the shade must be 466° C, count- 

 ing from the date of leafing. This number is more especially appli- 

 cable to the vineyards of Champagne and Burgundy, and is not 

 necessarily strictly applicable to P^pernay or to the vineyards of 

 the south of France. The fifth and subsequent columns of the 

 table give the mean climatic conditions for a period of sixteen days, 

 in the middle of which is the calculated date of flowering. There 

 appears to be no simple relation between this latter data and the 

 resulting wine crop, nor has the crop any apparent relation with the 

 total sky radiation during this period. In fact we may conclude that 

 up to the time of flowering the energy of the vine has been devoted 

 to building up its own structure as a preparation for the work that is 

 to come. The development of the grape does not depend upon nitrog- 

 enous particles stored away in the vine, but on the power to elaborate 

 the sap which is to become the juice of the grape, and that power 

 depends upon the leaf surface, the roots, and the stock during the 

 first stages of the growth of the grape, but eventually upon changes 

 that go on within the grape itself. 



These facts are brought out by the study of the conditions prevail- 

 ing during the last stages, viz, from flowering to maturity : 



According to Gasparin the grape reaches its maturity when it has 

 received a sum total of mean daily shade temperatures of 1,926° C, 

 counting from the date of flowering, but the grape ceases to be 

 nourished or to ripen when the mean daily temperature falls lielow 

 12.5°, If, now, we ascertain the date of maturity by summing up 

 the daily temperatures, as required by Gasparin's rule, we obtain 

 the results given in the first column of the following table. If we 

 2667—05 >i 17 



