406 



Notes on the Ifijf/uefice [No. 36, 



of their information, and I have, in fact, remarked, that in spring, 

 all the plants are more forward in the vicinity of woods and that 

 violets are found in flower on their borders much earlier than in. 

 the open plain or on the naked hill. The forests, therefore, pro- 

 tect the ground from the cold in the north, but what is not a little 

 wonderful, they shelter it from the heat in warm climates. These 

 two opposite effects proceed only from the different forms and dis- 

 positions of their foliage. In the north the leaves of the pine, the 

 larch, the fir, the cedar, and the juniper are slender, glossy and 

 varnished ; from their smallness, their polish, and the variety of 

 their directions they reflect the heat around them in a thousand 

 ways producing nearly the same efieet as the hair of the animals of 

 the north whose furs are warmer in proportion as their hair is 

 more fine and glossy. Besides, the leaves of several species, aa 

 the fir and the birch, are suspended perpendicularly from their 

 branches by long moveable stalks, so that with the least breath of 

 wind, they reflect around them the rays of the sun, like mirrors. 

 In the south, on the contrary, the palm, the talipot, the cocoa and 

 the banana bear large leaves which on the side towards the ground 

 are rather dull than glossy, and which extending horizontally, 

 throw a broad shade beneath them, without any reflection of heat; 

 I admit, nevertheless, that the clearing away of forests dispels the 

 cold arising from humidity, but it increases the dry and piercing 

 cold of the north, as experience has proved on the lofty mountains 

 of Norway which were formerly cultivated, but are now uninhabit« 

 able because they have been totally stripped of their woods. This 

 clearing of the ground likewise increases the heat in warm coun- 

 tries, as I have observed in the Isle of France on several hiUs, 

 which, since all the trees have been destroyed, are become so diy 

 as to be at present incapable of cultivation. The grass which 

 grows on them during the rainy seasons, is in a short time burned 

 by the sun. What is still worse, in consequence of the aridity of 

 these hiUs a great number of streams are dried up : for trees 

 planted on eminences attract the humidity of the air and fix it 

 there, as we shall see in the study that treats of plants. Besides, 

 by destroying the trees which are on high grounds, the vallies are 

 deprived of their natural manures, and the plains of the skreens 

 which shelter them from the high winds. These are in some 



