33S COSMOS. 



plicated nature of these disturbing causes (which involuntarily 

 remind us of those which the near and especially the smallest 

 cosmical bodies, the satellites, comets, and shooting stars, are 

 subjected to in their course) increases the difficulty of giving a 

 lull explanation of these involved meteorological phenomena, 

 and likewise limits, or wholly precludes, the possibility of that 

 predetermination of atmospheric changes which would be so 

 important for horticulture, agriculture, and navigation, no less 

 than for the comfort and enjoyment of life. Those who place 

 the value of meteorology in this problematic species of predic- 

 tion rather than in the knowledge of the phenomena them- 

 selves, are firmly convinced that this branch of science, on ac- 

 count of which so many expeditions to distant mountainous 

 regions have been undertaken, has not made any very consid- 

 erable progress for centuries past. The confidence which they 

 refuse to the physicist they yield to changes of the moon, and 

 to certain days marked in the calendar by the superstition of 

 a by-gone age. 



" Great local deviations from the distribution of the mean 

 temperature are of rare occurrence, the variations being in 

 general uniformly distributed over extensive tracts of land. 

 .The deviation, after attaining its maximum at a certain point, 

 gradually decreases to its limits ; when these are passed, how- 

 ever, decided deviations are observed in the opposite direction. 

 Similar relations of weather extend more frequently from south 

 to north than from west to east. At the close of the year 1820 

 (when I had just completed my Siberian journey), the maxi 

 mum of cold was at Berlin, while North America enjoyed an 

 unusually high temperature. It is an entirely arbitrary as- 

 sumption to believe that a hot summer succeeds a severe win- 

 ter, and that a cool summer is preceded by a mild winter." 

 Opposite relations of weather in contiguous countries, or in 

 two corn-growing continents, give rise to a beneficent equali- 

 zation in the prices of the products of the vine, and of agricul- 

 tural and horticultural cultivation. It has been justly re- 

 marked, that it is the barometer alone which indicates to us 

 the changes that occur in the pressure of the air throughout 

 all the aerial strata from the place of observation to the ex- 

 tremest confines of the atmosphere, while* the thermometer 

 and psychrometer only acquaint us with all the variation^ oc- 

 curring in the local heat and moisture of the lower strata of 



* Kamtz, in Schumacher's Jahrbuch fur 1838, s. 285. Regarding 

 the opposite distribution of heat in the east and the w est of Europe and 

 North America, see Dove, Repertorium der Physik, bd iii., s. 392-393 



