14 THE ROTHAMSTED EXPERIMENTS. 



field and feeding results, it has been thought that the most 

 appropriate, and at the same time the most useful course, will 

 be to give as complete a view as practicable of the plan and 

 results of some of the field and feeding experiments themselves, 

 and to enforce the lessons which they teach by such reference 

 to laboratory results as the questions raised require for their 

 elucidation, and as space will permit. In other words, the 

 analytical and other laboratory work must be treated as essential 

 means to an important end, and cannot, within the limits of this 

 review, be made the subject of critical consideration as such ; and 

 here it should be observed that nothing is done at Eothamsted, 

 in the way of manure, or feeding-stuff analysis, or seed control, 

 for any purposes external to those of the investigation. 



Although, as has been said, a large amount of field, feeding, and 

 analytical results still remains unpublished, yet fortunately a 

 much larger amount has already been put on record. Hence 

 it may be that some of our readers will be disposed to say that 

 they knew much of what is here given before. On the other 

 hand, probably a larger number are not so well acquainted with 

 what has been written ; and most may probably feel that the 

 outline here provided will serve the useful purpose of assisting 

 them the more effectively to study the fuller published records. 

 Indeed, the object in view throughout has been to afford guid- 

 ance for further study, rather than to attempt the impossible 

 task of giving anything like an adequate account of the very 

 numerous and varied results that have been obtained. 



As a useful preliminary to further explanation of the plan of 

 illustration proposed, it will be convenient to call attention to 

 the general arrangement of the field experiments, and also to 

 their extent and duration, as given in Table I. 



In further explanation, it may be stated that the general plan 

 of the field experiments has been, to grow some of the most im- 

 portant crops of rotation, each separately, year after year, for 

 many years in succession on the same land, without manure, 

 with farmyard manure, and with a great variety of chemical 

 manures ; the same description of manure being, as a rule, ap- 

 plied year after year on the same plot. Besides the experi- 

 ments on the growth of individual crops year after year on the 

 same land under different conditions as to manuring, what may 

 be called complementary experiments have been made on the 

 growth of crops in an actual course of rotation, without and with 

 different manures ; also others on the mixed herbage of per- 

 manent grass-land, both without and with various manures. It 

 is to be understood that the arrangement of the manures is made 

 entirely regardless of the comparative cost as between plot and 

 plot, the question at issue being one of constituents against con- 

 stituents, and not of shillings against shillings. 



