NEW 
« TO IMPROVE THE SOIL AND MIND.” 
SERIES. 
Vol. IV. 
ALBANY, JULY, 1847. 
No. 7. 
ACTION AND INGREDIENTS OF MANURES, 
LETTER TO PROF. WEBSTER. 
Giessen , May 1, 1846. 
My Dkar Sir —The discovery of ammonia in soils, 
to which I alluded in my last, and the important results 
to which it must' lead, will appear in clearer light after 
a brief consideration of the subject of manures. 
The time is not long gone by, when plants were sup¬ 
posed to owe their growth to some mysterious creative 
power, the living principle possessed. This opinion, 
since the element of quantity has been carried from phy¬ 
sics into the other departments of science, and especial¬ 
ly into chemistry, has gradually lost its supporters. 
Occasionally, however, a man may be found, who de¬ 
murs to a new doctrine in agricultural chemistry, with 
the expression—“ You have not taken into proper con¬ 
sideration the action of the vital principle.” 
It is, nevertheless, well known, that without water, 
plants will not grow; and that they flourish better in 
some soils than in others; and that the addition of ma¬ 
nures has been instrumental in greatly augmenting the 
produce of fields. 
What the essential ingredients of manures are, and 
how they act, and what are the sources of the ingredi¬ 
ents of plants, especially of carbon and nitrogen, have 
been objects of repeated investigation by some of the 
first scientific men of the age. 
You will remember that Saussure recognized, some 
time since, alkalies and alkaline earths in the ashes of 
plants; but found them in such variable proportions, that 
he came to the conclusion that they were'.non-essential, 
—occurring in the plants merely because they were 
present in the soil in a soluble state. 
You are aware that Boussingault has expressed the 
opinion, after a variety of experiments, that the value 
of a manure is in near relation to its per centage of am¬ 
monia. 
Mulder, has, you know’ - , written much in support of 
the view' that ulmic and humic acids, ulmates and bu¬ 
rn ates, etc., in one form and another, minister largely 
to vegetation. And in the last volume of Berzelius’ 
Jahrs-Bericht, received a day or two since, I see the 
above-named distinguished chemist has been recently 
conducting a series of experiments, lending, in his view, 
support to his previously expressed opinions. 
Liebig differs from them all. He found that thou«-h 
the relative amounts of magnesia and lime, .potash and 
soda, occurring in the ashes of a Savoy pine, and of the 
same species grown elsewhere, might be greatly unlike. 
—the amount of oxygen in combination with the metals, 
calcium, magnesium, potassium, sodium 'and iron, of 
the ashes, was a constant quantity. This observation 
bears the stamp of its great author, and its importance 
can only be estimated in connection w r ith a detailed ex¬ 
position of the evolution of organic acids, alkaloids, and 
indifferent bodies in-, the vegetable organism. Of this 
you will not expect me here to write. 
This great law he discovered and laid down : that for 
the full development of the organic tissues of each spe¬ 
cies, a certain per centage of inorganic bases is indis¬ 
pensable; and that of these, potash, fro a certain amount, 
may replace soda, and magnesia lime; but the amount 
of oxygen 7nust be constant. 
In other words, the equivalents of base must be a 
constant quantity for each species. 
When you take in hand a number of ash analyses of 
the same species of plant grown on different soils, and 
calculate therefrom the per centage of oxygen of the 
bases, you will find that the results differ but little from 
each other. For different species the per centages of 
oxygen vary, as do also the relative and absolute 
amounts of the several bases and acids. 
Liebig, as you are already aware, takes the position 
that the sources of carbon and nitrogen are carbonic 
acid*ahd ammonia of the air, and not soluble organic 
bodies met with in some soils. He asks if it be not so, 
wdiere the thousands of tons of wmod, grown for centu¬ 
ries in succession, on a soil containing but traces of or¬ 
ganic matter, have derived their carbon ? And again: 
What replaces the nitrogen shipped from Holland in 
hundreds of thousands of pounds of cheese yearly, if 
the ammonia does not home from something besides de¬ 
caying organic matter? 
A meadow, yielding year after year, without ma¬ 
nure, an uniform moderate crop, by addition of gypsum, 
had its produce increased a third. The addition of 
ashes increased its production another third; and the 
distribution of bone ashes another third. 
So here, by the addition of mineral matters, its ca¬ 
pacity of production had been doubled. No new source 
of carbon had been provided—no new source of ammo 
nia—and yet the hay gathered after the additions of 
mineral matter, contained twice as much carbon, and 
at least twice as much nitrogen as before. 
Where did these ingredients come from ? 
Boussingault’s ingenious experiments with regard to 
the sources of carbon, had yielded a partial answer. 
The carbon came from the carbonic acid of the air. 
The ammonia, as you will presently perceive, could 
have had no other origin. 
Farraday, I need not mention to you, found ammonia 
in almost all bodies. Even metals, dropped in fused 
potash, yielded ammonia. Sand, heated to redness, and 
poured, upon cooling, along the back of the hand, im¬ 
mediately after, yielded ammonia. 
