44 



mental Oat crop was grown in 1869, and the last in 

 1878, after which, owing to the wetness and the foul- 

 ness of the land, it was left fallow for several years, 

 and then the experiment was finally discontinued. The 

 results obtained were, however, sufficient to show the 

 general similarity in manurial requirement of oats and 

 the other cereals, wheat and barley ; and although there 

 are obviously points of difference also that it would 

 have been of interest further to investigate, the diffi- 

 culty of keeping such crops clean when grown year 

 after year on the same land, proved a sufficient obstacle 

 to the continuance of the experiment. 



The numerical results of the Field experiments are 

 recorded in the "Memoranda" They have not been 

 systematically discussed in any separate paper ; but 

 attention has been called to their more important 

 indications in my Oxford Lectures. 



Samples of the produce of each plot, both grain and 

 straw, were taken each year, and the dry matter and 

 ash determined in them. In the case of 3 of the 

 plots, the nitrogen also has been determined, in pro- 

 portionally mixed samples of the produce (of grain and 

 straw separately), of the first 4 years, 1869-72. 



Soil samples were also taken, to the depth of 

 9 inches only, from 2 of the plots in 1874, which was 

 the sixth year of the experiment; and in these the 

 nitrogen (by soda-lime) has been determined. 



X. EXPERIMENTS ON THE ALTERNATION OF WHEAT AND 

 BEANS, IN GEESCROFT FIELD. 



A portion of the Field, comprising 10 plots, on which 

 peas had been grown for 4 years, 1847-50, was then 

 devoted to the growth of beans and wheat alternately ; 

 the respective plots being differently manured for the,, 

 beans, but unmanured for the succeeding wheat. The 

 experiment was continued without a break for 16 years ; 

 and for 12 years more somewhat irregularly, owing to 

 the wetness and foulness of the land ; and, for the same 



