172 The Rothamsted Agricultural Experiments. 
laboratory and sample room, to be bequeathed to a trust for the 
continuance of the work after his death, which took place in 1900. 
This is not the place to give even the briefest summary of the 
splendid results of Lawes’ and Gilbert’s work. Our present object 
is to direct attention to some of the more striking botanical lessons- 
to be learned from a visit to Rothamsted at the present day. 
On the death of Sir Henry Gilbert at the end of 1901, Mr. A. D. 
Hall, at that time Principal of the South Eastern Agricultural 
College at Wye, was appointed Director of the Station by the 
Lawes Trustees, and he is not only carrying on the unbroken 
series of manuring experiments inaugurated by Lawes and Gilbert, 
but has also started important new lines of research. 
Some of the lessons of the Rothamsted experiments were 
developed by Mr. Hall in the lectures he gave last autumn for the 
University of London at the Chelsea Physic Garden on “The 
Constitution of the Plant in Relation to Soil,” and many of those 
who attended these lectures have recently had an opportunity of 
visiting Rothamsted and seeing for themselves, under Mr. Hall’s 
guidance, some of the effects of the differences of nutrition to which 
various agricultural crops have been subjected for so many years. 
Effect of Manuring on Meadow-Land. 
Perhaps the most striking and instructive experiments from a 
general botanical point of view are those which shew the effects of 
long continued differential manuring of meadow land. In 1856 an 
area of about seven acres of land in Rothamsted Park, which had 
been permanent grass for at least 200 years, was divided into a 
number of plots for differential treatment, and since that time each 
plot has been continuously treated with a definite quantity of a 
particular manure. Twice every year the grass is cut and an 
estimate is made, not only of the total weight of hay from each plot, 
in cwts. per acre, but also of the botanical composition of the hay, 
i.e. of the percentages of the different species of plants in the total 
dry weight of the crop. 
The cumulative effect of the differential manuring, not only on 
the quantities of hay produced but especially on the species of 
plants growing on the different plots, is most stirikngly evident to an 
observer visiting the experimental area in the middle of June, just 
before the cutting of the grass. One plot will be bright with butter¬ 
cups and sorrel, while the adjoining one shews not a single flower, 
but is entirely composed of tall dark-green meadow-grasses, and a 
third is covered with the graceful white umbels of Anthriscus. 
