24 HOW CROPS GROW. 



practice by developing theory. In 1851 the Agricultural Society of Leip- 

 zig, (Lcipziger Oeconomlsche Societcet), established an Acfl Experiment 

 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, Thuringia, 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 larii'e number 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 Landwlrthschaftliclien 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- 

 cuniary 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. 



