I 



CLIMATOLOGY. 



325 



Baltic (52^ 30' lat.), where a wine is produced that can 

 scarcely be considered potable, these numbers are as follows : 

 47'^0, 31°, 630-7, and 47'^-o. If it should appear strange 

 that the great differences indicated by the influence of climate 

 on the production of wine should not be more clearly manifest- 

 ed by our thermometers, the circumstance will appear less 

 singular when we remember that a thermometer standing in 

 the shade, and protected from the effect of direct insolation 

 and nocturnal radiation can not, at all seasons of the year, and 

 during all periodic changes of heat, indicate the true superficial 

 temperature of the ground exposed to the whole effect of the 

 sun's rays. 



The same relations which exist between the equable littoral 

 climate of the peninsula of Brittany, and the lower winter and 



The great accordance in the distribution of the annual temperature 

 through the different seasons, as presented by the results obtained for 

 the valleys of the Rhine and Maine, tends to confirm the accuracy of 

 these meteorological observations. The months of December, January, 

 and February are reckoned as winter months. When the different 

 qualities of the wines produced in Franconia, and in the countries 

 around the Baltic, are compared with the mean summer and autumn 

 temperature of Wilrzburg and Berlin, we are almost surprised to find 

 a difference of only about two degrees. The difference in the spring 

 is about four degrees. The influence of late May frosts on the flower- 

 ing season, and after a coi-respondingly cold winter, is almost as iiii 

 portant an element as the time of the subsequent ripening of the grape, 

 and the influence of direct, not diffused, light of the unclouded sun 

 The difference alluded to in the text between the true temperature of 

 the surface of the ground and the indications of a thermometer sus 

 pended in the shade and protected from extraneous influences, is in 

 ierred by Dove from a consideration of the results of fifteen years' ob 

 servations made at the Chiswick Gardens. See Dove, in Bericht i'lhe^ 

 die Verhandl. der Berl. Akad. der Wisa., August, 1844, s. 285. 



