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of this article. But the questions—Whence are they derived ? and how 
are they distributed to form the different parts of the tree ? is of vital im¬ 
portance to the success of the fruit grower, and these questions I now 
propose to answer : 
1st. Oxygen is found every where, and there is scarcely a known sub¬ 
stance into the composition of which it does not enter. It forms one-fifth 
part of the healthy atmosphere—of all the water in and about the globe 
eight in every nine parts are pure oxygen. It enters as a component into 
every part of the vegetable, and into every substance with which it is in 
contact. The only trouble then, which we need give ourselves, about a 
supply of oxygen to our trees, is to see that the earth about the roots is 
kept in that light and porous condition which will readily admit the air 
to them. 
2d. Hydrogen.—This, though not so abundantly diffused as oxygen, 
exists in small quantities in almost as many substances. We have just 
said that oxygen constitutes eight in every 9 parts of water—the ninth 
part is hydrogen. It is found in almost every animal and vegetable sub¬ 
stance—the tree, so long as it has a supply of moisture, will have no 
difficulty in supplying itself with this element. 
3d. Nitrogen forms four-fifths of the'atmosphere, and is consequently 
at all times largely in contact with the branches and leaves of the tree—- 
but let it not be forgotten, that very little of it is taken into the tree by 
these parts.* It is mostly taken up by the roots, being derived by them 
from the ammonia with which they are in contact. It is no less important 
to remember that a very large proportion of all the nitrogen taken into 
the plant or tree is used for the production of the flower and the fruit, 
and that it is the great stimulant to the production of these important 
parts. I call particular attention to this fact, as upon the proper appli¬ 
cation of it will depend much of the success of the horticulturist. The 
reader unlearned in vegetable chemistry may here ask, “ Where is the 
ammonia from which the tree derives its nitrogen V* I answer, that al¬ 
though it is contained largely in the atmosphere, and is washed into the 
earth by the descending rain water, yet the chief supply, or that abun- 
* I am aware of differing on this point with Liebig, but as the limits of this article 
■will not admit of a discussion of this question, I must rest satisfied with my own state¬ 
ment, supported by the opinions of a large majority of agricultural chemists. 
