THE BATTLE OF LIFE. 105 



dependent on climatal variations. In endeavouring to give 

 an idea of the effect of different manures in influencing the 

 nature and fierceness of the struggle, it will be convenient 

 to allude first to those cases in which no change has been 

 made in the condition of manuring, mentioning first those 

 plots in which comparatively simple manures are employed, 

 and afterwards those in which a more complex manure is 

 employed. 



Mineral manures alone. One of the plots at Rot ham - 

 sted illustrates the effects of mineral manures consisting of 

 admixtures of various earthy and alkaline salts used by 

 themselves, without the admixture of nitrogenous sub- 

 stances. Speaking generally, it is there observed that, 

 while graminaceous herbage has, with much fluctuation, 

 slightly increased, the proportionate amount of leguminous 

 plants, as compared with grasses, has on the whole been 

 largely increased, although latterly it has shown a tendency 

 to decline. This large increase is mainly due to Latkyrus 

 pratenxis, which prevails over all its fellows. The grasses 

 which hold their own best are Festuca ovina, Agrostis 

 vulgaris, and Holcus lanatus. Achillea Millefolium has 

 increased considerably, Conopodiumdenudatum &ud.Rumex 

 Acetosa, have usually been abundant. This description of 

 manure seems unfavourable to most of the weeds of pasture- 

 land other than the above mentioned. The crop is generally 

 moderate, with an even and early ripening, and a marked 

 tendency to stemmy as distinguished from leafy growth, 

 the colour of the foliage being of a light yellowish green. 



On the wheat plots, it has been shown that purely mineral 

 manures scarcely increase the yield at all, though they are 

 beneficial to the leguminous crops. These experiments 



