DISCURSIVE. 117 



REVELATIONS OF THE SPECTROSCOPE. 



It has been discovered by the spectroscope, that light, when traversing a 

 leaf, shows an abundance of green and red rays, which are not utilized by 

 the plant. Tbis, doubtless, accounts for the fact that some young trees 

 will not live in the dense shade of the parent tree. Trees differ, too, in 

 the quality of the light that is absorbed and transmitted. Doubtless the 

 mosses and liverworts enjoy the red rays, for they will thrive luxuriantly 

 under the densest forest shade. Some of our forest trees, the ash for 

 instance, will live under the shade of other trees, where a different species 

 will die. Some of the rays transmitted, for instance, by the box elder, 

 whose shade predominates, may be absorbed by the ash. A beech will 

 grow under the shade of an oak better than the young oak itself. In such 

 cases different species of trees mutually support each other. It has been 

 observed that the box elder does less injury to grass and grain under its 

 shade than some other species. The elder seems to favor the growth of 

 grass, while the broad-spreading butternut excels most trees as a monopo- 

 list it injures both grain and grass. 



EFFECT OF TREE-SHADOWS. 



The effect of the shadows of different species of trees elongated, for 

 instance, in the morning sun, is very marked. Though the shadows may 

 be equally dense, the injury on cultivated plants is very unlike. Whether 

 there is any peculiar chemical action, imparted by the tree, cast forward 

 into and with the shadow, we know not; the more plausible inference is, 

 on the data here given, that certain rays are absorbed more by the leaves 

 of one tree than another. These experimentations corroborate our obser- 

 vations, demonstrating that trees do better where a variety of species are 

 growing side by side, than they do under our set method of having only 

 one species or variety on the lot. 



WORK OF THE TREES. 



"The tree of the field is man's life," said the inspired law-giver of the 

 Hebrews. In this short sentence, written over three thousand years ago, 

 is condensed all that trees do for us. They give us life. Without them 

 we could not live. In destroying them we destroy our means of existence. 

 To the outward eye a tree is a very plain, simple thing, with its root, 

 stem and branch, wood, bark and leaf, given to us to provide shade and 

 fruit, and to gratify our sense for the beautiful with its form and color. 

 But much more than this is there. There are invisible powers working 

 ceaselessly within and around it, which control and direct the machinery 

 of the world. As we study the origin and life of a tree, we learn with 

 wonder the mighty preparation made for its coming on earth, and the 



