66 THE CONICAL GROWTH OF TREES. 



hill, pour together their tributary waters, which, united, 

 form the broad river which rolls on to the ocean. 



But, although the number of leaves of the whole tree, as 

 of each branch, from year to year continues to increase, 

 yet the thickness of the conical layers, after a certain point 

 of time in the development of the main axis or stem, as 

 regularly diminishes. The cause of this decrease in the 

 breadth of the wood-rings arises from the fact, that the 

 surface of the enveloping cones continually increases as 

 the tree gets older, so that the formative material, from 

 the leaves, is spread over a more and more extended area. 

 N^ow, up to a certain period in the life of the tree, the in- 

 crease of leaf-surface in the atmosphere keeps pace with the 

 gradually increasing surface of the cones, and this produces 

 that uniformity of breadth which characterizes the wood- 

 rings formed each season ; but, when the main stem and 

 branches of the tree approach the maximum of their deve- 

 lopment, owing to the diminished vital activity of the leaves, 

 less woody matter is formed, which still continues to be 

 spread over a constantly increasing extent of conical sur- 

 face ; hence the thickness of the woody strata gradually 

 diminishes as the tree draws nearer to the limit of its life. 



It is thus that, in the course of centuries, solid and en- 

 during vegetable monuments are reared ; trees which out- 

 live the successive generations of man — Abroad at the base, 

 and tapering to the extremities. Nature builds on the 

 conical principle to insure their stability ; and the dark 

 and sombre forests of oak, pine, and fir, which clothe the 

 sides of mountain, whose summits rise above the snow- 

 line, are constructed on the same architectural principles 

 as the mountains themselves ; for the avalanche loosening 

 from its mountain heights, and coming down with an ac- 

 celerated rush into the subjacent valleys, and the leaf 

 falling from the tree, are both detached from cones. Such 

 is the beauty, simplicity, and grandeur of the works of 

 l^ature ! 



Keader, startle not at the boldness of this language. It 

 is strictly true. Great and little are but relative terms, 

 distinctions made by finite and imperfect minds. Sir 



