if conducted v iiv a truly 'scientific manner, so as to be applicable for the 

 solution of questions of fundamental and general interest, Prof. Msercker 

 concluded that the only field experiments which it was practicable to 

 carry out in Germany were such as should be conducted by the practical 

 farmer himself, to test the applicability to practice, of results and conclu- 

 sions otherwise arrived at ; and that, to insure that even such experi- 

 ments should not be misleading, similar ones should be conducted on 

 different descriptions of soil, and for several years in succession. 



That the great cost of scientifically conducted field experiments should 

 have prevented the more extended prosecution of them, is perhaps not 

 surprising when I tell you that the Rothamsted field experiments, inde- 

 pendently of all the laboratory investigations connected with them, cost 

 considerably more than ^1000 annually ; whilst those which have been 

 undertaken by the Duke of Bedford at Woburn for the past seven years, 

 on behalf of the Royal Agricultural Society of England, and which are 

 under the direction of Dr. Vcelcker, cost not much less than this. 



At various institutions in America, and preeminently at the New 

 Jersey Agricultural Experiment Station, very much good work is being 

 done of the character prosecuted with so much success in Germany, and 

 recommended by Prof. Msercker to be still further followed up ; and 

 whilst such work should be continued and extended, surely investiga- 

 tions of a more permanent value, and of more general application, 

 should not be neglected. Nor can it be supposed that in so wealthy a 

 country as America, where there is so much munificence and public 

 spirit displayed in all matters of progress, the cost of scientifically con- 

 ducted agricultural experiments will be any obstacle. 



This brings me to the special subject-matter of my lecture, which is to 

 illustrate the value of long continued and carefully conducted experiments, 

 by reference to the results of one series of such experiments conducted 

 at Rothamsted, namely, those on the growth of wheat for more than 

 forty years in succession on the same land ^vithout manure, with farm- 

 yard manure, and with a great variety of chemical manures. 



But, before entering upon the details of this subject, it will be well to 

 give some account of the scope and plan of the whole investigation, of 

 which these special results only form a part. 



At Rothamsted, no questions of mere local interest or economy are 

 undertaken. The object is rather to investigate the principles under- 

 lying fundamental practices ; and whilst results obtained in one locality, 

 on one description of soil, and with one character of climate, require to 

 be carefully studied before conclusions applicable to other localities and 

 to other countries can be drawn, yet it is believed that the results which 

 have been obtained are of very general and wide application. 



The general scope and plan of the field experiments has been to 

 grow some of the most important crops of rotation, each separately, year 

 after year, for many years in succession on the same land, without ma- 

 nure, with farm-yard manure, and with a great variety of chemical ma- 

 nures, the same description of manure being, as a rule, applied year after 

 year on the same plot. Experiments with different manures on the 

 mixed herbage of permanent grass-land, on the effects of fallow, and 

 on an actual course of rotation, without manure, and with different 

 manures, have likewise been made. Field experiments have thus been 

 conducted for the periods, and over the areas, indicated in the following 

 table: 



