388 



BIRCH. 



which has most unwisely crept in, of treating of one of 

 two subjects which are inseparably connected both in 

 nature and in the ordinary course of human thought, 

 and wholly omitting the other. 



Besides the length to which it has already extended, 

 there are some other reasons why the structural part 

 of the inquiry should not be included in this article. 

 The anatomy of the human body is a distinct science, 

 and will be found treated of as largely as is neces- 

 sary for popular purposes in the first division of this 

 Cyclopaedia; and, as there is no living action in 

 man in which the mind is not concerned, the con- 

 sideration of the organ can be much more usefully 

 introduced along with its subservience to the mental 

 physiology ; and consequently all which remains 

 farther to be said of man, as an object of natural 

 history, can be more clearly as well as more briefly 

 expressed in the article MAN, which the student may 

 read as a sequel or accompaniment to what has been 

 here stated. 



BIRCH (Bctula). A genus of forest trees, of 

 which there are several specks ; and some of the 

 species, or at least what are considered as species, are 

 apt to run into varieties. 



The common birch, Bclula alba, is very abundant 

 in the northern parts of Europe ; and there are still 

 extensive natural woods of it in many places of the 

 highlands of Scotland : nor is it altogether unknown 

 as an indigenous plant in the uplands of South Bri- 

 tain. It is, perhaps, the most hardy of all the forest 

 trees, and the one which is found uppermost upon 

 the mountains, and nearest to the pole at least it is 

 much more so than any other indigenous tree. 



On the mountain-tops it is exceedingly small, and 

 quite the miniature of a tree, with a stem not thicker 

 than a quill, leaves not larger than those of duck- 

 weed on a pond, if indeed as large ; and altogether 

 not more than from half a foot to a foot in height. 

 Still, however, even where it is most dwarfed it pos- 

 sesses the proper form of a tree, and does not run into 

 a shrub, as on the moors of Sussex and other parts 

 of the south of England. 



No tree is, indeed, more liable to have its size 

 altered by situation than the birch ; and when it is so 

 altered, all the parts of it may be said to alter in the 

 same proportion. The leaves are small, and the twigs 

 slender in proportion as the height and thickness of 

 the trunk are less. It is only in very peculiar places 

 of the Scottish mountains that the dwarf birch is met 

 with in the full perfection of its littleness and tree- 

 like habit. Those situations are high mountains, the 

 summits of which present not cliffs, but terraces of 

 mould ; and the dwarf birches are met with on the 

 southern exposure, a very little below the snow. 



In the sheltered dells and bottoms, and especially 

 by the banks of clear running streams, when these do 

 not consist of bog or peat, but of patches of rich 

 mould with rock interspersed, the birch becomes not 

 an unstately tree, and it is certainly a very beautiful 

 one. The bark, which on the specimens exposed to 

 the blast of the hill is torn and broken by cracks and 

 fissures, is, on the rich and sheltered ground, of a 

 delicate white colour. The green, too, is exceedingly 

 delicate, especially in the early part of the season ; 

 and scarcely any foliage can rival in tint that of a 

 copse or grove of thriving birches at that season of 

 the year. It has this further advantage, that the 

 scent of birch leaves when they expand, and, indeed, 

 up almost to the period when their vegetable action 



ceases, have a very fragrant and exceedingly refresh- 

 ing scent. The tree is one of the sweet-juiced class, 

 though the bark is astringent ; and grass grows better 

 under or in its shade, and suffers less by its drip, than 

 in the case of almost any other tree. 



The most beautiful habit of the tree is when its 

 branches are slender and pendent, forming what is 

 called a weeping birch. Authors sometimes >t;ite 

 that the weeping birch is a different species from tin? 

 common ; but in the wild birch woods of the Highlands 

 weeping birches occur so frequently on the richer 

 grounds, and especially on the banks of the streams 

 and birches which do not weep, on the more barren 

 exposed places, that it is scarcely possible they can 

 be different species. In confirmation of their being 

 the same, we may mention that it is a saying in some 

 parts of the Highlands, that" The birch is ail!y tree, 

 for it weeps most where it has the least cause." 



Birch. 



On the banks of some of the larger rivers, just 

 before they leave the mountains, birch trees ofien 

 assume a very interesting character. The fibres of 

 their roots clutch the projecting pieces of rock, as if 

 they were the talons of birds of prey, penetrating 

 downwards to a considerable depth. In effecting 

 this the power of vegetable action within will some- 

 times open a crevice where the lightest stone it has to 

 move is many tons, they thus draw a copious nourish- 

 ment for the trees, as well as give them a firm support. 

 In favourable exposures the height may be forty, fifty, 

 or even sixty feet, though the trunk is rarely, indeed, 

 so much as one foot in diameter. 



In these situations the pendent or weeping twigs, 

 seldom thicker than packthread, are often forty or 

 fifty feet long, and wave most gracefully in the little 

 winds which are sporting. over the waters in those 

 wild places. 



The points of those twigs are often bathed in the 

 pools, or they play in the waterfalls, and a cascade 

 among rocky grounds, with weeping birches, is per- 



