303 Wisconsin State Hoeticultukal Society. 



our success in agriculture than any other one which may be stated. 

 The confidence in the correctness of the current opinion, that the 

 presence of these mineral constituents in an available form in the 

 soil is essential for the reproduction of any plant from its seeds, 

 is so firmly established in the minds of thinking agriculturists 

 that we are apt to forget how recent the date when the first com- 

 prehensive experimental investigations in that direction rendered 

 the existence of these relations between soil and plant more 

 conspicuous. It seems at the present time almost incredible to 

 notice in the writings of Justus von Liebig that, as late as 1830, 

 one of the leading botanists of the University of Berlin, 

 Sprengel, still asserted that ground bones are of no use as a fer- 

 tilizer in Germany ; or that the distinguished French chemist, 

 Dumas, even ten years later, considered the mineral constituents 

 of plants a mere incidental feature in the vegetable economy ; or 

 that before 1840 not one pound of Peruvian guano was used upon 

 the farms of Europe, although Alexander von Humboldt, in 

 1814, had described its use as a fertilizer in Peru, and some ship- 

 loads of that material had found their way to the London market. 

 In citing these instances I need not state that neither Liebig nor 

 any other well-informed student of the agricultural practice in 

 previous ages denied the high appreciation of wood-ashes, bones, 

 gypsum, lime, marl, and other mineral substances, besides the 

 various. kinds of animal manures, in the farm management of 

 earlier times. Modern rational agriculture does not rest its claim 

 of progress on the mere introduction of any particular new mode 

 of operation. For to try to maintain a remunerative fertility of 

 the soil under cultivation by fallow and the rotation of crops, or 

 to enrich one portion of the farm lands at the expense of another 

 one by retaining a certain proportion of meadows and pastures to 

 secure manure for the grain-bearing lands ; or to enrich the sur- 

 face soil at the expense of the subsoil by raising deep-rooting 

 plants, as root crops, or leguminous crops, as clover, etc., for fodder 

 and manure; or to improve the natural productiveness of the 

 lands by deep ploughing, or by drainage, or by irrigation, are all 

 modes of farm practice known, more or less, for hundreds of 

 years. Our real progress in this direction consists mainly in the 



