DEVOTED EXCLUSIVELY TO THE IMPROVEMENT OF SOUTHERN AGRICCLTURE, 
VOL. XIII. : AUGUSTA, GA., AUGUST, 1855’ NO. 8. 
WILLIAM S. JONES, Publisher, 
DANIEL LEE, M. D., and D. REDMOND, Editors. 
SEE TERMS OX LAST PAGE. 
’A = 
CiniiDnu} ani Histellanij. 
THE CRITICAL STUDY OF AGRICULTURE. 
The Cultivator has many readers who desire to in- 
vestigate, and understand, as far as practicable, the prin- 
ciples of agriculture as a scientific profession. To aid 
studious planters and others in mastering the theory of 
the most advanced tillage and husbandry, is a duty which 
we must not neglect, even if it subjects us to the charge 
of discussing themes not entirely plain to all the readers 
of this journal. While it deals pretty largely in mere 
recipes, or simple directions for pursuing farming opera- 
tions of all kinds, it should not overlook the substratum 
of all sound practice, namely, the true principles of agri- 
culture, These have their origin in the nature of things, 
as God has created them ; and nothing short of the most 
carefully conducted researches to unfold the essential na- 
ture of things agricultural, can reveal the Laws which 
should govern the daily labors of the plantation. Rocks, 
soils, plants and animals, produce the multifarious and 
complex results which we witness, not by mere chance, 
but in obedience to natural laws enacted by an all-wise 
LaW-Giver. A man of genuine science studies habitually 
the sublime teachings of nature, and thereby imbibes both 
knowledge and wisdom from the perennial fountain of all 
V/isdom. 
The substance for which farmers now pay the largest 
price to increase their crops, is called ammonia, whose 
action in imparting fertility to poor land is a matter of 
deep interest, not less as a practical than a scientific 
question. Kuhlman (see Comptes Rendus, 17, p. 1118- 
1130,) remarks as follows ; “ In order to understand fully 
die action of the salts of ammonia, it is necessary to point 
out the fact that they serve to facilitate the passage of other 
substances into the plant. Phosphate of lime, phosphate 
of magnesia, and silica, are somewhat soluble in water 
containing carbonate of ammonia, and thus become ab- 
sorbable. Every soil contains carbonate of lime, which 
is rarely free from alkali, and this, under the influence of 
the sun’s heat, decomposes the sal-ammoniac and sulphate 
of ammonia, whereby soluble lime salts and carbonate of 
ammonia are formeL Thus the amonia salts are not 
only the chief means of supplying nitrogen to the plant. 
but they also serve as a medium for facilitating the pas- 
sage of those substances into the plant, which are indis- 
pensable to its development. No wonder then that they 
operate so favorably,” 
Before proceeding to analyze the above statements, it 
may not be amiss to remark that the the market value of 
Peruvian Guano is regulated mainly by the amount of am- 
monia contained therein ; and to say that, ammonia itself, 
is nothing more than two invisible gasses, nitrogen and 
hydrogen, chemically combined. 
Kuhlman is not wholly correct in saying “ every soil 
contains carbonate o lime which is rarely free from alkali,’' 
meaning potash and soda. It is true, the analysis of 
common limestone rarely fails to give traces of a small 
per centage of the alkalies named ; but there are large 
areas of arable land, and particularly in the Southern 
Atlantic States, formed not from the dedris of lime and 
other aqueous rocks, but from granite, and its kindred 
formations in situ. In such soils, lime, magnesia, potash 
and soda, exist mainly as silicates, not as carbonates, 
phosphates, or sulphates. Primarily these silicates in 
granitic deposits are insoluble in pure water, which is one 
cause of the comparative poverty of such lands. Water, 
charged with carbonic acid, or with carbonate of am- 
monia, as stated by Kuhlman, both of which we always 
treat as manure- water, renders lime, magnesia, potash and 
soda available, and also the flint or silicic acid with which 
they were combined. Silicic acid, (pure flint sand,) com- 
bines with ammonia in a way to form a soluble salt, which 
may easily be decomposed in the stems of wheat, corn 
and cane, leaving the flint to impart solidity and strength, 
to the outer tissues of the plant, while the ammonia may 
partly escape into the atmosphere, and partly supply 
available nitrogen to the pabulum within, which demands 
this element for its organization and growth. The two 
most important working agencies in all manure, whether 
derived from the excrement of animals, or decaying vege- 
tables consumed by them, are ammonia and carbonic 
acid. This acid and alkali united, make the common 
smelling salts sold in shops. 
In 1852, BoussiNGAULTdetermined with his accustomed 
care and accuracy, the quantity of carbonic acid in the 
air enclosed in a good soil, and found it, in some cases, 
to be four hundred times larger than in the atmosphere! 
This is a highly interesting and suggestive fact, to one 
familiar with the power of carbonated water to decom- 
pose all insoluble silicates, which really form the mass of 
tilled earth. So long as the soil has the proper physical 
properties, from perfect comminution and porousness it 
is admirably adapted to collect and condense fertilizing 
gasses near the roots of needy plants. But no mere rae"^ 
chanical arrangement of particles will secure fruitfulness 
