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XXIV. — On the Scientific Principles hy ivhich the Application of 

 Manures might to be regulated. A Lecture, delivered at 

 Oxford by Charles Daubeny, M.D., F.R.S., M.R.I. A., 

 Sec, Sibthorpian Professor of Rural Economy. 



It may assist us, perhaps, in understanding tbe mode in which 

 the various matters intermixed with the soil, with the view of 

 improving its quality, may be supposed to operate, if we begin 

 with tracing the successive steps by which mankind have ad- 

 vanced from the simplicity of early practice to that more compli- 

 cated and artificial system of husbandry which prevails in most 

 civilized countries at the present day. 



In order to become acquainted with the rude methods adopted 

 in the first ages of the world, it is scarcely necessary to go back 

 to the records or traditions of that period : w'ithout giving our- 

 selves this trouble, w^e may obtain a sufficiently just idea of their 

 mode of procedure by referring to the practice of husbandry 

 adopted by the early colonists in the wilds of America, or by 

 that in use amongst those who in the present day emigrate from 

 the eastern portions of the United States into the regions of 

 the far west. 



In the virgin land on which the labours of these first settlers 

 were expended, whether it were in Virginia and the Carolinas 

 in the last century, or in Kentucky and Michigan in the present, 

 the expedients for refreshing and invigorating the soil which 

 are resorted to in older countries are found to be wholly super- 

 fluous. 



Judging indeed from the crops obtained for several years 

 after it has been first reduced to cultivation, the ground might 

 in many instances be pronounced to possess an inexhaustible 

 store of fertility, since the same crops admit of being repeated 

 year after year, with no apparent diminution in the amount 

 of produce, and with no further care on the part of the co- 

 lonist than that of simply turning up the soil and introducing 

 seed. 



Such is represented to have been the case even with the to- 

 bacco when first cultivated by the early settlers in Virginia, 

 where, on land now requiring careful tillage, and yielding but 

 a scanty return, this exhausting species of crop is said to have 

 been repeated year after year without any perceptible diminution. 



In Kentucky we are told of soil that has yielded the finest 

 crops of wheat or of maize for twenty-five or even for fifty suc- 

 cessive years, and that without the addition of any kind of ma- 

 nure, whilst in the State of Illinois some portions of the terri- 

 tory are said to have been cultivated with profit in this same way 

 from the first period at w^hich the country was settled. 



