INTHODli TION 13 



eiven to si>tiu« of tlie eiirly hooks on ganicMiiiif,'. i-. j;., ParkiuHon's 

 "Pannlisiis Torrestris" (1G29), whiob is an iifrount of the oma- 

 mpntal plantii of that period. 



14<i. Kinjj's hook on "The Soil" t-xphiins the intimate 

 relation of pliysionl forces to the prodiietivity of the land; and 

 the author in Professor of Agricultural Physics in the University 

 of Wisconsin. There is a Bureau of Soils in the National 

 Department of Agriculture, the work of which is largely in 

 the field of soil physics. The physical or mechanical analysis 

 of soils is now considered to be as important ns the chemical 

 analysis. Some of the physical aspects of farm soils ar»< dis- 

 cussed in our chapters ii.. iii., iv., v. 



Ida. Fk'ology (written a»cology in the dictionaries) is the 

 science which treats of the relationship of organisms (that is, 

 plants and animals) to each other and to their environments. 

 It is animal and vegetahle economy, or the general e.xternal 

 phenomena of the living world. It has to do with modes and 

 hahits of life, as of struggle for existence, migrations and 

 nesting of birds, distribution of animals and plants, influence 

 of climate on oruanisms, the way in which any plant or animal 

 behaves, and the like. Darwiu's works are rich in ecological 

 obser^'ations. 



IC). Environment is the sum of conditions or surroundings 

 or circumstances in which any organism lives. An environment 

 of any plant is the compound condition produced by soil, 

 climate, altitude, struggle for existence, and so on. 



I8a. It is customary to consider agricultural chemistry as 

 the fundaweutal science of agriculture. Works on agricultural 

 chemistry are often called works on agriculture. But agricul- 

 ture has no single fundamental science. Its success, as we 

 h.ivK Bf>«n, depi-nds upon a union of business methods and the 

 ipj'l. I'lons of science; ami this science, in its turn, is a co^irdi- 

 nation of many sciences. Chemistry is only one of the scH>nccs 

 which contribute to n better agriculture. Under the inspiration 

 of Davy. Liebig, and their followers, agricultural chemistry made 

 the first great application of science to agriculture; and upon 

 this foundation haii grown ttte experiment -station ulen. It i*> 



