212 THE ALDER. 



In Russia an oil is extracted from the Birch, which is 

 used in the preparation of Eussian leather. For this 

 purpose, the white bark, taken either from recent trees, or 

 from the decayed trees which are found in the woods, is 

 gathered into a heap, and pressed into a pit shaped like 

 a funnel ; it is then set on fire, and covered with turf. 



The oil which trickles down the sides drops into a vessel 

 placed to receive it, and is then stowed away in casks. 

 The purest oil swims at the top, and when used for 

 anointing leather not only imparts a fragrant odour, but 

 makes it durable. Owing to the presence of this oil, books 

 bound in Eussian leather are not liable to become mouldy ; 

 they also prevent mouldiness in books bound in other 

 leather which happen to be near them. 



The Birch is liable to a disease which shows itself by 

 producing on the upper branches large tufts of twigs, which 

 seen at a distance resemble crows' nests. How it origi- 

 nates is unknown, some persons assigning it to the punc- 

 ture of an insect, others to peculiarity in the soil. 



A district species of Birch, Betula nana, Dwarf Birch, 

 is found in Scotland and in all the northern countries of 

 continental Europe and America. It is a low wiry shrub, 

 rarely exceeding three feet in height, with numerous round 

 notched leaves, which are beautifully veined. By the 

 Laplander it is applied to the same purpose as the twigs 

 of the larger kind. 



THE ALDEE, 



ALNUS GLUTIXOSA. 



Natural Order AMENTACE.E. 



Class MOXQECI A. Order TETRANDRI A. 



THIS tree is botanically distinguished from the preceding 

 by having its fertile catkins oval, and its seeds not winged, 

 whereas the fertile catkins of the Birch are cylindrical, and 



