GEOGRAPHY OF PLANTS. 



479 



We liere perceive tliat the mean temperature of the period, during which the 

 growth and maturation of the grapes take place, exercises a very remarkable 

 influence. The temperatures of the summer and autumn of 1834, and conse- 

 quently that of the entire growing season, were decidedly greater than that of 

 any others noted above, and in the same year the strongest wine was produced. 

 The temperature of the beginning of autumn — September, of 1835 — is next in 

 order, as higher than that of the remaining years, and though the summer of 

 1S36 was warmer, we find the wine of 1835 superior to that of 1836. This 

 clearly indicates that a summer heat, prolonged into the autumn, is of more 

 value than high summer heats, with a lower temperature, later in the .season. 

 The value of the wines produced in the remaining years is nearly in accordance 

 with the temperature of the beginning of autumu, or the month of September, 

 and that for 1833, when the growing season was the lowest, and that for Sep- 

 tember reduced to a minimum, the wine, it is said, was scarcely drinkable. 

 The mean temperature, therefore, of the summer is not a safe criterion for 

 judging of the ada^jtatiou of a district to vine culture. A mild autumn must 

 be regarded as one of the essential conditions, and, consequently, the mean for 

 the entire period of growth where the higher heat is near the termination of that 

 cycle, becomes a better evidence of fitness of any region for producing wine of the 

 highest quality. This truth is strongly indorsed by the observations made in 

 1811, so remarkable over Europe for the quantity and excellence of its wines. 

 This year, known as the " comet year," was distinguished by the high tem- 

 perature of the early autumn. Though the summer mean was lower than 

 several of the years above tabulated, and about an average, the months of Sep- 

 tember and October were maintained at 59^ Fahrenheit, while the usual tem- 

 perature of these months had not been higher than 52.7° Fahrenheit, or nearly 

 seven degrees lower. Boussingault, to whom we are indebted for much of the 

 data on the meteorological conditions necessary to the production of wine of 

 the best quality, has expressed his conclusions in the following terms : 



"That iu addition to a .summer and an autumn sufficiently liot, it is indispensable tLat 

 at a given period — that which follows the appearance of the seeds — there should be a mouth 

 the mean temperature of which does not fail below G6.2° Fahrenheit." 



'iihe following table illustrates the cultivation of the vine in Europe, and al?o 

 the depreciation of its produce according to climatic relations. Cherbourg in 

 Normandy, in northwestern France, Dublin, and London, show, in a remarka- 

 ble manner, how, with annual mean temperatures about the same, or higher than 

 those of several places in the interior of the continent, and a winter tempera- 

 ture much milder, yet the summer heat falling several degrees below, and the 

 temperature of the hottest month differing more Avidely, the grape cannot be 

 cultivated in Ireland, Britain, or Normandy. The more general prevalence of 



