9 



more compensation to be awarded in some cases than in 

 others. It is only by working in this manner that real justice 

 can be done to all parties. 



LESSONS TAUGHT BY FIELD EXPEEIMENTS. 



I turn now to the second part of my subject. I want to 

 bring before you, and especially before the valuers who may 

 be present, the results of actual trials in the field, which supply 

 examples of the returns obtainable from the residues of 

 previous manuring, and which show how the value of these 

 residues will vary under different circumstances. One could 

 wish that the facts which must most influence our judgment 

 had been far more numerous, but though few they are worthy 

 of our best attention. The practical results I am about to 

 mention are gathered from the field experiments made at 

 Eothamsted and at Woburn. Unpublished details respecting 

 the Eothamsted experiments have been kindly placed at my 

 disposal by Sir J. B. Lawes and Sir J. H. Gilbert, and re- 

 specting the Woburn experiments by Dr. J. A. Voelcker, for 

 the purposes of this lecture. 



It is well at starting to remember that the soils at these 

 two stations are very different. At Eothamsted the surface 

 soil is a heavy loam with flint stones ; the subsoil is usually 

 clay ; at a considerable distance from the surface is the chalk, 

 which provides a good natural drainage. The rotation field 

 has, I think, the heaviest soil ; that of the barley field is 

 lighter. The Woburn soil is quite different ; it is a deep soil 

 consisting entirely of very fine sand. At the commencement 

 of the experiments it was in a foul condition, a fact which 

 disturbs the earliest results ; it has since proved very fertile. 

 It contains, however, but little lime. 



1. Residues of titrates. 



The first point to which I would call attention is the 

 difference in the behaviour of residues of ammonia salts and 

 nitrates on these two soils. At Eothamsted, since 1852, there 

 have been two plots (plots 17 and 18) in the wheat field on 

 which the manures have alternated each year. Every spring 1 

 one plot receives as a top dressing 400 Ibs. of ammonia salts 

 1 The application has been in the spring since 1878. 



