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strengthen the growth and improve the luxuriance of the plant. The 
surface may not furnish all the nutriment to the growing blade. There 
may be airs, healthful and pestilent, which impart nourishment, or in¬ 
fection to the waving blade. There may be innunterous agents which are 
fructifying or baleful, of which observation has made no discovery. 
There are doubts upon the subjects of which most is known.* There 
are questions suggested to the superficial which the profound observer 
cannot answer, and they are such as affect the common practical effect of 
applications that are daily made to the soil. That certain articles possess 
fertilizing properties, is proven by all experience. It is known that ap¬ 
plications of ammonia, of lime, of vegetable matter, will increase the 
yield of certain plants. The same facts are arrived at by scientific analy¬ 
sis. But it is not known what exact amount is necessary to be applied 
in order to secure the proper luxuriance of leaves and stalk consistent 
with the just support of the fruit—by which the greatest yield at the 
least expense is secured. Much may be wasted by over application— 
much lost by insufficient supply, of fertilizers. It is not known, the pro¬ 
portional value of these agents to the multiplicity of crops ; whether there 
may not be better and cheaper fructifying agents than any now known; 
and whether the effect is wrought by single qualities, or by a combina¬ 
tion of single causes with each other, with the soil, and with undiscover¬ 
ed or apparent elements in the air and earth. It is not known by what 
process moisture enlivens the plant—whether by an innate and fertilizing 
property it possesses, or by dissolving other fertilizers in the soil, and 
enabling them to enter the minute pores of the roots and rootlets, or by 
forming gases that the breathing leaf may inspire. Finally, nothing is, or 
perhaps can be known, that will remedy the unpropitiousness of seasons, 
that will supply the want of moisture in the atmosphere, that will pre¬ 
serve the plant from its native and peculiar accidents, from the severities 
of winter and the unwholesome heat of summer. 
These are the difficulties that science has overcome, or has still to en¬ 
counter. Its triumphs have been great. Its labor has been one of bene¬ 
ficence. The benefits which it has confered on mankind are substanstial 
and enduring. But science is slow and long. It is not based on specu¬ 
lation or hypothesis, but on the experience of ages. Science is the re¬ 
duction of facts to their primal causes and principles. It must be con- 
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