FROM MIRBEL. 281 



frosts destroy ,them j witness, the vineyards round 

 Paris : the plantations there which escape the injuries 

 of frost, are not those which look towards the south, 

 but those that look towards the north. The sap of 

 the latter is set in motion late, and when the heat 

 reaches them the season is already settled, and no risk 

 is run from the inroad of cold. 



Late frosts are peculiarly hurtful to the delicate 

 American and Botany Bay plants, which we are at- 

 tempting to naturalize in Europe. Many of these will 

 bear a very sharp cold in the heart of winter ; but no 

 sooner does the spring advance, and a softer air prevail, 

 than their roots begin to elaborate their juices under 

 ground, their bark to fill with moisture, their buds to 

 swell and open, and a fall in the temperature if but for 

 one moment destroys them. 



In proportion as we advance towards the Pole, we 

 are sensible of a change in the appearance of the vege 

 tation. The species which require a mild and tempe- 

 rate climate, are supplied by others which delight in 

 cold. The forests fill with pines, firs, and birches, 

 the natural decoration of a northern, laiuL The birch, 

 of all trees, is the one that bears the severity of the 

 climate the longest ; but the nearer it approaches the 

 Pole, the smaller it grows ; its trunk dwindles and be- 

 comes stunted, and the branches knotty, till at last it 

 ceases to grow at all towards the 70th degree of lati- 

 tude, the point where man gives up the cultivation of 

 corn. Further on, shrubs, bushes, and herbaceous 

 plants only are to be met with. Wild Thyme, Daph- 

 nes, Creeping Willows, and Brambles, cover the face 

 of the rocks. It is in these cold regions that the ber- 

 ries of the Rubus Rusticus acquire their delicious fla- 

 vour and perfume. Shrubs disappear in their tun>> 

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