300 NOTKS OX THE BOT.'.NT OF KXPKIilMKXTAI, GRASS-riOTS. 



in diverse combinations, of the elements nitrogen, phosphorus, potas- 

 Bium, sodium, &c., or those elements wliich are indispensably neces- 

 pary in the lite of the plant, and of which the soil is soonest exhausted. 

 Tlie rleniciits, in short, which must be supplied by man to ground under 

 constant cultivation, in contradistiiictiou to such elements as carbon 

 and the constituents of water, the supply of which is inexhaustible. 



It is also important to remember that these elements, especially 

 the metals, some of which are known to be intimately associated with 

 the activity of certain vital functions, as iron in the production of 

 chlorophyl, and potassium in the assimilating powers of the latter, form 

 together only a very small proportion of the total weight of vegetable 

 organisms. It has also been asserted by some physiologists that plants 

 are unable to attain their proper development in a soil or atmosphere 

 overcharged with certain elements. Be that as it ma)', a glance at the 

 large wall-case exhibited by Mr. Lawes in the Loan Collection at 

 South Kensington, or a visit to the ex2>erimental ground at liotham- 

 sted, will at once impress the mind with the strikingly different 

 results obtained in the character and (quantity of the herbage under the 

 influence of diverse manures. Having betn employed by Mr. Lawes 

 for some time on these experiments, the results of which have not yet 

 been sufficiently elaborated for publication, I thought botanists 

 would welcome some notes on the flora of the area under experiment, 

 as they might render the forthcoming exhaustive memoir more inte- 

 resting and intelligible, and at the same time draw more general 

 attention to the experiments themselves. 



Although the results of my work and that of others, which, of 

 course, belong' to Mr. Lawes, have only partially been made public, that 

 gentleman kindly assented to my request to be permitted to use some 

 of the knowledge obtained while in his service. Naturally I shall 

 avoid giving information here that would detract from the interest of 

 the approaching report. ]\[y object is rather to create a desire in some 

 botanists to make themselves familiar with the nature and signiflcance 

 of these experiments, because I believe that they furuisli the material 

 for solving various problems and interesting (questions in plant life — 

 problems requiring much time and some scientitic training to work 

 them out. In fact, my experience at Kothamsted was that every fresh 

 step suggested some new line of inquiry. 



Within the limits of this article I can only run over the surface of 

 the prominent features of the composition of the vegetation of the 

 experimental grounds. To attempt to give in a few words an idea of 

 the whole subject would only be confusing. 



From time to time Messrs. Lawes and Gilbert have published 

 Tarious reports on these experiments in the " Journal of the Agri- 

 cultural Society," the principal one relating to analyses of the propor- 

 tions, or percentages, of the various species constituting the herbage 

 of each plot. To this paper the reader is referred for much information 

 relative to the manuring and the general eflects at that date. The meadow- 

 land under experiment is a portion of Kothamsted Park, about seven 

 acres in extent, and nearly level. The soil is a somewhat clayey loam, 

 and appears to be tolerably uniform throughout, with a clayey subsoil 

 of several feet in depth, immediately overlying the chalk, llespect- 

 iug its condition when the experiments were coaimeuced, it is stated iu 



