PHILOSOPHICAL TRANSACTIONS. 



VII. Memoir on the Rotation of Crops, and on the Quantity of Inorganic Mattei^s 



abstracted from the Soil hy various Plants under different circumstances. 



By Charles Daubeny, M.D., F.R.S., S^c, Honorary Member of the Royal English 



Agricultural Society, and Professor of Rural Economy in the University of Oxford. 



Received May 5,— Read May 22, 1845. 

 Contents. 



Introduction. 



Part I. — On the quantity of produce obtained from the several plots of ground, each year throughout the period 



during which the experiments were continued. 

 Part II. — On the chemical composition of certain crops cultivated in the Botanic Garden, and on the amount 



of inorganic principles abstracted by them from the soil during the period the experiments were conducted. 

 Part III. — On the chemical composition of the soil in which the crops were grown, and on the proportion of 



its ingredients that was available for the purposes of vegetation. 



Introduction. 



In laying before this Society an account of certain experiments which I have under- 

 taken with the view of elucidating the principles upon which the advantage of a ro- 

 tation of crops in husbandry depends, it may be proper that I should in the first 

 instance state the circumstances under which they were commenced, as well as those 

 which led me during the course of them to deviate in some respects from my original 

 plan of proceeding. 



During the prosecution of a set of researches which embraced a period of more 

 than ten years, it might naturally be expected, that the views at first entertained 

 would become modified, and that arrangements deemed sufficient for carrying out 

 the original plan should appear unsatisfactory, in proportion as glimpses of other 

 truths, than those which enlightened us at the outset, began to open upon the field of 

 our inquiry. 



Thus, when first I determined to apply a portion of the ground at my disposal to 

 experiments having reference to the rotation of crops, the scientific world was gCr 



MDCCCXLV. 2 B 



