— 
_————_—_——_ 
70 AGRICULTOR. 
rented or leased. In England it needs to be 
made in writing for a lease of more than three 
years ; and, though an unwritten one for a less 
period than three years will suffice, yet, for the 
sake of both parties, an agreement ought, in 
every case, to be in writing. In Scotland a lease 
of land is not susceptible of proof upon mere 
parole evidence, if for more than a single year; 
and either party is entitled to resile at the end 
of each successive year. An agreement to make 
a lease amounts, in equity, to an actual lease ; 
but whether any particular agreement constitutes 
a present lease, or alease to commence at some 
future period, depends on the intention of the 
parties, and must be ascertained from its own 
language. See article Lzass. 
AGRICULTORor Acricutturist. A person who 
is Skilled in the art and science of cultivating land. 
Agricultor is the pure Latin name, and agricultu- 
| rest is the modified name in common English use. 
An agriculturist is a scientific person, and may 
or may not be engaged in actual farming ; and a 
farmer is a practical person, and may or may not 
| have a knowledge of the scientific principles of 
his art. 
AGRICULTURAL CHEMISTRY. The science 
which professes to teach the application of the 
established principles of chemistry, in regular 
and systematic form, to the theory and practice 
of agriculture. “Agricultural chemistry,” says 
Sir H. Davy in his opening lecture on this sub- 
ject, “has for its object all those changes in the 
arrangements of matter connected with the 
growth and nourishment of plants,—the compar- 
ative values of their produce as food,—the consti- 
tution of soils,—the manner in which lands are 
enriched by manure, or rendered fertile by the 
different processes of cultivation.” 
In 1795 the Earl of Dundonald addressed a 
‘Treatise showing the intimate connexion that 
subsists between Agriculture and Chemistry,’ to 
the cultivators of the soil in Great Britain and 
Ireland, and the proprietors of West Indian 
estates. The Karl, adopting the language and 
espousing the enlightened views of the French 
chemists of the day, drew together much element- 
ary matter on the composition of earths and 
vegetables, and the treatment of soils for agri- 
cultural purposes on just chemical principles ; 
but his lordship’s book was generally disregarded 
as the speculation of a mere theorist unworthy 
the attention of ‘practical men,—as if practice 
alone is not almost as fruitful in mistakes as mere 
theory. Sir Humphrey Davy’s course of lectures 
before the Board of Agriculture from the year 
1802 to 1812, attracted some attention to the theo- 
retical cultivation of agriculture, particularly the 
analysis of soils, the mutual effects of vegetables 
and the atmosphere,—the doctrine of manures,— 
and the proper rotation of crops. Since the pub- 
lication of these lectures, in 1814, various impor- 
tant contributions to scientific agriculture, or in 
|| explanation of the principles which ought to 
AGRICULTURAL CHEMISTRY. 
regulate the practice of the agriculturist, have 
been made both in our own country and on the 
continent. The writings of Berzelius, Mitscher- 
lich, Mulder, Johnston, and Liebig,—of the lat- 
ter especially—have developed the special and 
important bearings of chemical science on agri- 
cultural art in a way which must command the 
attention of all whose occupations or interests 
are connected with the cultivation of the soil. 
“The development,” says Liebig, “of the stem, 
leaves, blossoms, and fruit of plants is dependent 
on certain conditions, the knowledge of which 
enables us to exercise some influence on their in- 
ternal constituents as well as on their size. It 
is the duty of the natural philosopher to discover 
what these conditions are; for the fundamental 
principles of agriculture must be based on a 
knowledge of them. There is no profession which 
can be compared in importance with that of 
agriculture, for to it belongs the production of 
food for man and animals; on it depends the 
welfare and development of the whole human 
species, the riches of states, and all commerce. 
There is no other profession in which the appli- 
cation of correct principle is productive of more 
beneficial effects, or is of greater and more de- 
cided influence. 
“Tn addition to the general conditions, such as 
heat, light, moisture, and the component parts 
of the atmosphere, which are necessary for the 
growth of all plants, certain substances are found 
to exercise a peculiar influence on the develop- 
ment of particular families. These substances | 
either are already contained in the soil, or are sup- 
plied to it in the form of the matters known under 
the general name of manure. But what does the 
soil contain? And what are the components of | 
the substances used as manure? Until these 
points are satisfactorily determined, a rational | 
system of agriculture cannot exist. The power 
and knowledge of the physiologist, of the agri- 
culturist and chemist must be united for the 
complete solution of these questions; and, in or- 
der to attain this end, a commencement must be 
made. 
“Mhe general object of agriculture is to produce 
in the most advantageous manner certain quali- 
ties, or 2 maximum size, in certain parts or or- 
gans of particular plants. Now, this object can 
be attained only by the application of those sub- 
stances which we know to be indispensable to the 
development of these parts or organs, or by sup- 
plying the conditions necessary to the produc- 
tion of the qualities desired. 
“The special object of agriculture is to obtain 
an abnormal development and production of cer- 
tain parts of plants, or of certain vegetable mat- 
ters, which are employed as food for man and 
animals, or for the purposes of industry. 
“The means employed for effecting these two 
purposes are very different. Thus the mode of 
culture employed for the purpose of procuring 
fine pliable straw for Florentine hats, is the very 
