DR. DAUBENY ON THE ROTATION OP CROPS, ETC. 



185 * 



With a view then to this part of the inquiry, I proposed to estimate, first, the amount 

 of ingredients severally present in the soil which might sooner or later become available 

 for the purposes of vegetation ; and secondly, that of those principles which were in 

 a state to be applied immediately to those uses. It would also have been instructive, 

 to determine, by a comparative analysis of the soil, in the state in which it was before, 

 and after the experiments had been instituted, the loss which had been occasioned 

 by the crops in both these particulars ; but as, from the reasons assigned, I had neg- 

 lected to examine the identical soil of the experimental garden before the researches 

 commenced, I was obliged to content myself with obtaining an approximation to its 

 probable constitution, by selecting for examination that taken from a portion of the 

 garden, which was immediately contiguous, but which had recently been manured, 

 and had borne good crops. 



Here also I was assisted by Mr. Way, who undertook the more laborious part of 

 the inquiry, namely, that of determining the entire amount of the available consti- 

 tuents present in certain of the soils, leaving to me the task of ascertaining merely 

 the nature of those which could be extracted by water. 



The investigation therefore divides itself naturally into three heads ; the first re- 

 specting the actual amount of the permanent and shifting crops each year obtained ; 

 the second, the chemical constitution of the ashes resulting from those which had 

 been burnt for the purpose of examination ; and the third, the nature of the actual 

 as well as of the available ingredients of the soil in which the crops had been reared. 



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. 



The following plants were made the subjects of experiment : — 



Spurge . . 



Potatoes . 



Barley . . 

 Turnips 



Hemp . . 



Flax. . . 



Beans . . 



Tobacco . 

 Poppies 

 Buckwheat 



Clover . . 



Oats . . . 



Beet . . . 



Mint . . 



Endive . . 



Parsley . . 



Euphorbia lathyrls 

 Solanum tuberosum 

 Hordeiim sativum 

 Brasslca rapa . 

 Cannabis satlva . 

 Linum usltatlsslmum 



from 1835 to 1838 

 from 1834 to 1844 

 from 1835 to 1844 

 from 1834 to 1844 

 from 1835 to 1844 

 from 1835 to 1844 



Flclafaba from 1835 to 1844 



Nlcotlana Tabacum . 

 Papaver somnlferum 

 Polyg onum fagopyrum 

 Trlfollum pratense 

 Avena satlva . . 

 Beta vulgaris . . 

 Mentha viridls 

 Clchorlum endlvia 

 Aplum petrosellnum 



from 1834 to 1844 

 from 1834 to 1844 

 from 1835 to 1844 

 from 1 834 to 1 844 

 from 1839 to 1844 

 from 1839 to 1844 

 from 1835 to 1844 

 from 1835 to 1844 

 from 1835 to 1844 



