304 OUTLINES OF NATURAL PHILOSOPHY. 



to the better and more extensive cultivation of the 

 ground. 



CESAR says, that the vine could not be cultivated in 

 Gaul on account of the severity of the winter. The 

 rein-deer was then an inhabitant of the Pyrenees. 

 The Tiber was sometimes frozen over, and the 

 ground about Rome covered with snow for several 

 weeks together. See HUME cm the Populousness of 

 Ancient Nations, Essays., vol. i. p. 451. edit. 1772. 

 DAINES BARRINGTON, Phil. Trans, vol. Iviii. (1768} 

 p. 58., &c. 



Cultivation may improve a climate, l mo , By the 

 draining of marshes, and lessening the evaporation, 

 which is so great a cause of cold ; 2 do , By turning 

 up the soil, and exposing it to the rays of the sun ; 

 S tio , By thinning or cutting down forests, which, 

 by their shade, prevented the penetration of the 

 sun^s rays. The improvement which is continually 

 taking place in the climate of North America, 

 proves that the power of man extends to the phe- 

 nomena, which, from the magnitude and variety of 

 their causes, appear most beyond its reach. At 

 Guiana in South America, the rainy season has 

 been shortened by the clearing of the country, and 

 the warmth has been greatly increased. It thun- 

 ders continually in the woods; rarely in the culti- 

 vated parts. BUFFON, Sup. torn. ix. p. 346. oc- 

 tavo. 



3 Wind. 



