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MESSRS. J. B. LAWES AND J. H. GILBERT ON THE RESULTS OF 
laborious experiment, both in the field and in the laboratory, and following up both the 
botany and the chemistry of the subject, we can hardly claim to have yet done much 
more than reach the threshold of a very comprehensive enquiry. Still, we hope to 
establish some points of general interest, and possibly to indicate promising paths of 
future research. 
From the title of our paper, it will at once be concluded that the experiments were 
originally undertaken and arranged from an agricultural point of view. But, as 
experimenting on the feeding of animals soon led us into lines of enquiry of even more 
interest to the chemist, the animal physiologist, and the dietetician than to the agri¬ 
culturist, so the investigation of the effects of different manures on the mixed herbage 
of grass land has led us far beyond the limits of a purely agricultural problem, and has 
afforded results of more interest to the botanist, the vegetable physiologist, and the 
chemist, than to the farmer. Indeed, agriculture—the most primitive, and commonly 
esteemed the rudest of the arts—requires for the elucidation of the principles involved 
in its various practices a very wide range of scientific enquiry ; and the investigation 
of them may, in its turn, contribute facts of interest to the student of various and 
very distinct branches of natural knowledge. 
It will be readily understood that, as a necessary foundation for the discussion of the 
botany and the chemistry of the subject, it will be essential first to put on record, and 
call attention to, what may be distinguished as the agricultural data. It is proposed, 
then, to arrange and consider the results obtained under the following heads :—■ 
Part I.—The Agricultural Results. 
Part II.—The Botanical Results. 
Part III.—The Chemical Results. 
It will facilitate the understanding of the very voluminous and very various expe¬ 
rimental details which are to follow, if the scope of the enquiry, and the general 
character of the results, are somewhat further, but still only briefly, indicated in this 
place. 
About seven acres in the Park at Rothamsted have been set apart for the experi¬ 
ments, and divided into plots. Two of these have been left without manure from the 
commencement; two Lave received ordinary farmyard manure ; whilst the remainder 
have each received a different description of artificial or chemical manure, the same 
being, except in special cases, applied year after year on the same plot. 
Referring first to the agricultural results , it may be premised that, ivithout manure , 
the produce of hay has varied from year to year, according to season, from about 8 cwts. 
to nearly 39 cwts. per acre, and the average yield has been about 23 cw r ts. per acre 
per annum. On the other hand, the plot the most heavily artificially manured, and 
yielding the highest amount of produce, has given an average of about 64 cwts. of hay 
per acre per annum, with a variation from year to year from under 40 cwts. to nearly 
