24 HOW CROPS GROW. 
practice by developing theory. In 1851 the Agricultural Society of Leip- 
zig, (Leipziger Occonomische Societet), established an Ag’l Haperiment 
Station on its farm at Moeckern, near that city. This example was soon 
imitated in other parts of Germany and the neighboring countries; and 
at the present writing, 1867, there are of similar Experiment Stations in 
operation—in Prussia 10, in Saxony 4, in Bavaria 3, in Austria 3, in 
Brunswick, Hesse, Thiringia, Anhalt, Wirtemberg, Baden, and Sweden, 1 
each, making a total of 26, chiefly sustained by, and operating in, the in- 
terest of the agriculturists of those countries. These stations give con- 
stant employment to 60 chemists and vegetable physiologists, of whom 
a large uumber are occupied largely or exclusively with theoretical in- 
vestigations, while the work of others is devoted to more practical mat- 
ters, as testing the value of commercial fertilizers. Since 1859 a journal, 
Die Landwirthschafilichen Versuchs-Stationen, (Ag’l Exp. Stations), has 
been published as the organ of these establishments, and the 9 volumes 
now completed, together with the numerous Reports of the Stations 
themselves, have largely contributed the facts that are made use of in 
the following pages. 
In this country some similar enterprises have been attempted, but 
have not been supported with a sufficient combination of talent and pe- 
euniary outlay to ensure any striking success in the direction of agri- 
cultural chemistry. An imitation of the example set by European as- 
sociations is well worthy the consideration of our State Ag’l Societies, 
many of which could easily command the funds for such an enterprise, 
It would be found that such a use of their resources would speedily 
strengthen their hold on the interest and regard of the communities 
they represent. 
Agricultural science, in its widest scope, comprehends a 
vast range of subjects. It includes something from nearly 
every department of human learning. 
The natural sciences of geology, meteorology, mechan- 
ics, physics, chemistry, botany, zoology and physiology, 
are most intimately related to it. It is not less concerned 
with social and political economy, with commerce and 
law. In the treatises of which this is the first, it will not 
be attempted to cover nearly all this ground, but some 
account will be given of certain subjects whose under- 
standing promises to be of the most direct service to the 
agriculturist. The theory of agriculture, as founded on 
chemical, physical, and physiological science, is the topic 
of this and the succeeding volume. 
