TRANSACTIONS OF SECTION K. 809 
It will be seen that phosphatic manures have. produced a large increase 
(Plots 1, 2, 8); that a nitrogenous manure has had little effect (Plot 4); that 
otash and lime in conjunction with phosphates have caused a moderate increase 
(Plots 5 and 6); and that lime by itself has had little effect, except at one station, 
where there was a moderate increase (Plot 7). It will further be noticed that in 
three of the five cases in which phosphates have proved beneficial the larger 
application of phosphatic manure has produced twice, or more than twice, the 
increase yielded by the smaller (half) quantity, although the latter would, in the 
opinion of farmers, be a liberal dressing. The normal action of manures is strictly 
governed by the ‘ law of diminishing returns, and this exception indicates that the 
benefit produced by phosphates on the herbage is not of the direct or ordinary kind. 
Inspection of the plots further shows that the immediate action of a phosphatic 
manure is on the Leguminosae only, and that the marked improvement which 
gradually takes place in the gramineous herbage is due to the soil-improving 
qualities of leguminous plants. 
Proof that phosphatic manures do not benefit the pasturage on poor clay soils 
in the absence of Leguminose is furnished by an experiment at Wenden Lofts in 
Essex. The soil was in every way adapted to the action of basic (phosphatic) 
slag, but as no Leguminose could he found it was surmised that slag would not 
improve the herbage. Some plots were marked off and manured with phosphates, 
potash, and lime alone, and in combination ; on other plots white clover (Trifolium 
repens) was sown, and some of the sown plots were treated with phosphates. 
None of the manures produced any effect on the natural herbage. Where clover 
was sown on unmanured land it grew, but the plants were small and valueless. 
Where phosphates were applied, however, there was a luxuriant growth, similar 
to that found on the Cockle Park pastures after treatment with basic slag. 
The failure of phosphates to benefit the Trowse pasture (see table) was not 
due to the absence of leguminous herbage, but to the dry character of the soil. 
Rapid growth and the benefits which follow it are impossible in the absence of 
a plentiful supply of moisture. Hence a marked improvement from phosphatic 
manures is usually seen only on medium and heavy soils. With a high and con- 
tinuous summer rainfall light soils would, however, show improvement. Of 
ordinary Leguminose, Trifolium repens is by far the most valuable in improving 
the soils of pastures. When properly fed and supplied with moisture it is capable 
of developing at an extraordinary rate. It is especially luxuriant when growing 
in association with Agrostis, which shelters it in winter and makes way for it in 
summer, In the presence of grasses which form a close turf white clover grows 
comparatively slowly. Next to Trifolium repens, Medicago lupulina is probably 
most useful in improving poor soils. It grows very luxuriantly in damp seasons. 
Trifolium minus and Lotus corniculatus are also of considerable value. The 
latter has been very abundant this year. Trifoliwm pratense is most useful where 
it grows, but it does not cover the surface so uniformly as the others, and it 
disappears more readily. 
The application of basic slag to pastures is now very common, but there have 
been no systematic attempts to utilise it in conjunction with white clover in such 
a way as to produce the maximum effects on the soil; and of the 93 millions of 
acres now under pasture in England it is likely that at least two millions might be 
improved so as to leave a net profit of 5s. per acre per annum if the white clover 
plant were cultivated as skilfully as most of our farm crops are. 
6. A New Method of Forming Nitrites and Nitrates. 
By Epwaxp Joun Russ, D.Sc., and Norman Situ, M.Sc. 
Whilst studying the oxidation of phosphorus in moist air the authors 
observed that ammonium nitrite and nitrate are invariably formed in this reaction, 
even when both air and phosphorus are carefully purified beforehand. Other 
oxidations have now been investigated, and in a number of cases the reaction 
appears to be accompanied by a simultaneous oxidation of nitrogen of the air, 
