70 TREE PLANTER'S MANUAL. 



forms itself into a compound of carbon and oxygen, carbon dioxide, com- 

 monly known as carbonic acid gas. This gas is found more or less in all 

 natural waters. Mineral waters contain it in large quantities. It issues 

 from the earth, particularly in the region of volcanoes. From our fires, 

 fsom our lungs, from the lungs of all animals, from the processes of alco- 

 holic fermentation and of decay of vegetable and animal matter, from even 

 the sugar in our ripened fruits as they fall to earth and undergo spontane- 

 ous changes, is evolved this gas, constantly flooding the air we breathe, and 

 yet its relative quantity in the air is small, about three parts in ten thou- 

 sand. 



NOT A POISON. 



Carbon dioxide is not a deadly poison, as reputed of it. The reason why 

 it is destructive to life, is because it does not contain the oxygen necessary 

 for breathing processes. One dies, then, by suffocation, as in drowning in 

 water. Wherever it is in excess oxygen not being in proportional bal- 

 ance there is danger. Air in which a candle will not burn is not fit to 

 breathe. 



THE CENTRAL ELEMENT. 



Yet this gas is the central element of organic nature. "There is not a 

 living thing," says Ira Kemsen, professor of chemistry in the Johns Hop- 

 kins University, "from the minutest microscopic animal to the mammoth, 

 from the moss to the giant tree, which does not contain this element as an 

 essential constituent." 



The plants root themselves in the mineral kingdom and evolve its ele- 

 ments to finer conditions. The food of animals largely comes from plants. 

 The food of plants largely comes from carbon dioxide of the air. The leaves 

 and other tissues of plants have the power to decompose the carbon dioxide 

 with the aid of the electric rays of the sun, appropriating the carbon and 

 giving the oxygen over to the animal kingdom. Thus each kingdom "lives 

 and thrives on what the other rejects." Under this beneficent balance of 

 nature the composition of the air is kept mainly constant. 



"When the life process stops in the animal or plant, decomposition be- 

 gins, and the final result of this, under ordinary circumstances, is the con- 

 version of the carbon into the dioxide." 



To what extent this retrogressive action goes it is difficult to determine. 

 The inference is that in unbalanced states of the gases, a certain percent- 

 age falls back into crystallization to be taken up again by the plants. For 

 even centuries we may locally unbalance nature, as in excessive deforest- 

 ation, but we cannot do it with impunity. Nature severely punishes the 

 spoiler. Man robs himself. Prof. Houston well says (Outlines of Forestry, 

 page 145) that in many cases the denudation of the soil produces a perma- 

 nent disturbance of nature, "from the inability of such section of the coun- 

 try to sustain plant life." 



STOKED ENERGY. 



Dana, in his Manual of Geology, page 323, argues, "That the carbon 

 which is now coal, and was once in plants of different kinds, has come 



