and Nations on the extent and situation of Forests. 245 



Occasionally, but very rarely, we hear of snow-showers, 

 but as soon as the snow has fallen, it melts away, and the 

 refrigeration of the air, which in a warm country is termed 

 cold, lasts for such a short period, that it produces no 

 sensible alteration on the high temperature of Italy. The 

 prevalence of this latter must be exclusively attributed to 

 the clearing of forests situated on the slopes of hills and 

 mountains. Accordingly, hoarfrost appears to have now be- 

 come one of the most rare occurrences. In France, hus- 

 bandry made but slow progress, and civilization dawned at a 

 much later period than in Italy ; in consequence, its physical 

 condition changed by long gradations only, and forests con- 

 tinued for a considerable time to overgrow the country, and to 

 impart an icy temperature. In Spain, according to the re- 

 port of Livy,* the snow falling in the winter of the year 218 

 ante Ch., lay, in the vicinity of the Ebro, for 30 days, to the 

 depth of 4 feet. In the beginning of the first century, the 

 whole north of France was covered with forests and morasses. 

 Tacitus states, t that in Germany the cold weather prevented 

 fruit from thriving and ripening, and, even 50 years ante Ch., 

 the grapes failed in the cold forests of Belgium. According to 

 Ovidjl the vine plantations were frequently destroyed with 

 frost, in countries where nothing similar is now witnessed ; 

 even the wine froze in open vessels, and the Black Sea was 

 not only covered with ice, but the coating so strong, that 

 heavy waggons could safely pass over. 



A temperature so low, and which, for instance, in the south- 

 ern districts of Germany, was lower by 8° R. (18° F.) than it is 

 now, occurs no longer in these and other countries of the same 

 latitude. We draw, therefore, the conclusion, that, about 1800 

 years ago, the forests exerted such a strong influence on the 

 climate, that the mean temperature of the coldest month stood 

 from 4° to 5° (9° to 11^*^ F.) lower than at present ; that Ger- 

 many, owing to its morasses and forests, was visited by winters 

 resembling those of western Russia. It follows, from obser- 

 vations, calculations, and historical traditions, that, in conse- 



* Liv. lib. xxi. 



t Tacit., German., p. 5, and CseBar da Bello Gall., lib. ii. cap. 2. 



; Eleg. 10. 



