action of the fungus, and the subsequent luxuriant growth and removal of the grasses.

It was certainly to be expected that nitrates would be formed in considerable quantity on the decay of the fungus (whether in the stage of mycelium or of more advanced development), and possibly also on that of residual products of the action of the mycelium on the nitrogenous organic matter of the soil. It is quite in accordance with the supposition that nitrates are formed, that the band of grass following the track of the fungus should have the dark green colour which characterises it. It is, however, difficult to trace the formation of nitrates in meadow land, or at any rate to determine the quantity in which they are produced, as, owing to the amount and activity of the vegetation, they are for the most part taken up as soon as they are formed. Nevertheless, determinations of nitrates were attempted in the cases of the Broadbalk Field and of the Park Fairy Ring soils. The CrumFrankland method was the one then in use, and was the one adopted. The soil extracts were purified by alcohol, but the chlorides were removed by silver. Under these circumstances the attack on the mercury was very feeble, and the nitrates present were undoubtedly under-estimated. The Broad balk soils of the second collection have since been analysed by Schlösing's method, which is more accurate in the case of such extracts. The results of the determinations are given in Table VI below.

TABLE VI.-Nitrogen as Nitrates per Million of Dry Fine Soil.

Broadbalk Fairy Ring Soils, collected June 18, 1877.

Broadbalk Fairy Ring Soils, collected September 15, 1877.

The Park Fairy Ring Soils, collected September 19, 1877.

The Park Fairy Ring Soils, collected April 25, 1878.

It will be seen that in the case of the second series of samples from the Broadbalk Field Ring, there was a very considerable amount of nitric acid in the soil of the ring-band. In all other cases the quantity, if any, was very small. It was, however, always more abundant in the soil of the ring-band than either within or without the circle.

In making the extracts of the surface soils for the determination of nitrates, it was observed that when mycelium was present, the watery extract was dark-coloured, and gave a bulky organic residue on evaporation. It is to be supposed, therefore, that some of the products of the decay of the mycelium, or of the action of the mycelium on the soil, will pass by drainage into the subsoil.

Some of the subsoils were examined for nitric acid, but scarcely more than a trace was found, excepting in the subsoil collected under the ring-band at the second sampling of the Broadbalk Field Ring soils, where the table shows the highest amount in the surface soils. Even here, however, the nitrogen as nitrates in the subsoil amounted to only 0.82 per million of the dry soil.

On a review of the whole of the results of our examinations of the soils of fairy rings, we think there can be no doubt that the source of the nitrogen of the fairy ring fungi is the organic nitrogen of the soil itself, which it assimilates, presumably, though not certainly, as organic nitrogen, and eventually deposits as manure which becomes available to the associated herbage. Further, the whole of the phenomena of the fairy rings, so far as the nitrogen is concerned, are thus explained without supposing any intervention of atmospheric nitrogen. Evidence is still wanting to prove whether at all, or in what degree,

some green-leaved plants have a power of assimilating the organic nitrogen of the soil, such as is possessed by the fungi. That Leguminosæ, for example, will take up more nitrogen from an arable soil than Gramineæ would from the same soil is certain. In some cases part, if not the whole, of the increased assimilation of nitrogen by the Leguminosa is doubtless due to the arrest of nitrates that would have been lost by drainage in the case of the growth of Gramineæ. In others, the evidence at command does not justify the conclusion that the whole of the increased amount can be so accounted for. Again, under the influence of potassium salts applied as manure, leguminous plants will take up a considerably increased amount of nitrogen, even from a poor arable soil; whilst under the same conditions a gramineous crop would not do so. This action is very marked when potash salts are applied to grass land. In this case, however, the percentage of nitrogen in the much richer surface soil is reduced in a degree easily determinable by the soda-lime method. The question arises, therefore, how far the increased amount of nitrogen taken up under these circumstances, is due to a liberation of soil-nitrogen independently of any direct action of the plant itself; or whether, under the influence of the potash supply, the plant acquires a character, or increased activity, of underground growth, by virtue of which it is enabled to take up the organic nitrogen of the soil in a manner, or in a degree, of which it is not otherwise capable? Some Leguminosa, however, which have very deeply distributed roots, have the power of assimilating very large amounts of nitrogen over a given area, when growing on arable soil with the surface impoverished, and the subsoil naturally poor, so far as nitrogen is concerned.

224

ANNIVERSARY MEETING.

March 30th, 1883.

Dr. J. H. Gilbert, F.R.S., President, in the Chair.

The following Report was read by the President :

According to the Bye-Laws, it is the duty of the President to present a report of the state of the Society at the Annual General Meeting of the Fellows. A glance at the Addresses of my predecessors shows that the obligation has been very variously interpreted, according to the special circumstances of the Society at the time, or to the special view of the President himself. There have been occasions when irportant questions affecting the interests of the Society had to be discussed-sometimes involving matters of internal working and management, at others the consideration of some new departure, with a view to more extended usefulness.

At present there are no such points requiring special notice. It is my duty rather to record steady progress in the attainment of the objects for which the Society was founded; and for myself, having been elected into the Society during its first Session, now within a few weeks of 42 years ago, it seems fitting that I should attempt to review the progress of the Society, in some important aspects, from the commencement of its existence up to the present time. I trust that such a review will not be without interest to the Fellows, and that it may even prove to be of some practical utility.

The Number of Fellows.-Obviously a very essential, though by no means the only necessary element, of the prosperity of a Society, the objects of which are defined to be-" The promotion of Chemistry and of those branches of Science immediately connected with it,"—is the number of Fellows it has attracted. I will, therefore, first call your attention to the progress of the Society in this respect.

Of the 25 gentlemen who met on February 23rd, 1841, for the purpose of taking into consideration the formation of a Chemical Society, the names of only two are still to be found in the list of our Fellows, Dr. Lyon Playfair, and Mr. Charles Heisch; and of the first Officers and Council, the name of not one is still there to be found. Indeed, of the 118 Members on the Register at the first Anniversary Meeting of the Society, held on March 30th, 1842, there remain only 12,

besides myself, who could now answer to the roll-call, namely, Professor Thomas Andrews, Mr. William Blythe, Dr. De la Rue, Mr. Charles Heisch, Mr. F. R. Hughes, Dr. G. D. Longstaff, Mr. Thomas Pearsall, Mr. J. Arthur Phillips, Dr. Lyon Playfair, Dr. E. Schunck, Mr. J. Denham Smith, and Dr. James Young.*

The following tabular statement shows the number of Ordinary Members or Fellows, of Associates, and of Honorary and Foreign Members, at the end of each period of five years, during the 40 years from 1841-2 to 1880-1 inclusive. It also shows, for comparison, the numbers for 1881-2, and for the year now closing, 1882–3:—

The following is a more detailed statement, in the usual form, of the Members for the past year 1882-3 :

:

Number of Fellows at the Anniversary, March 30th, 1882 1175 Since elected and paid admission fees

Removal on account of arrears.

Withdrawn..

Deceased...

104

* W. R. Grove, Esq. (now Mr. Justice Grove), was present at the meeting for the formation of the Society, and was on the first Council, but is not now on the list of the Society.