38 Agricultur, Horticultur, Forstbotanik. 



Freeman, W. G. and S. E. Chandler, The World's Com- 

 mercial Products. (Pitman & Sons, London. 1906. Parts 1—4. 

 pp. I-VIII. 1-28). 



The subtitle of this publication "A descriptive account of the 

 Economic Plants of the World and their commercial uses" will indicate 

 its scope. It will be completed in twelve fortnightly parts published 

 at 7 d. each. The parts already issued treat vf wheat, barley, oats, 

 rye, rice, millets, maize, starches, sugar and cacao. An account is 

 given of the plant or plants yielding each products, its occurrence, 

 cultivation, mode of collection or harvesting and the preparation and 

 uses of its products. The work is fully illustrated with photogravure 

 reproductions and coloured plates, and there are also maps showing 

 the geographical distribution of the more important plants. 



W. G. Freeman. 



Hall, A. D., On the accumulation of fertility by land 

 allowed to run wild. (Journ. agric. Sei. 1905. I, 2. p. 241—249). 



Describes the result of leaving two fields, untouched from 1882 

 to 1904. On one of the fields wheat had previously been grown for 

 40 years in succession. On being left to itself the wheat died out 

 completely in four years. Afterwards bushes and young trees were 

 removed from the ground but otherwise the Vegetation which natu- 

 rally established itself was not interfered with; this Vegetation 

 included about 25 per cent of leguminous plants. 



The second field had carried beans from 1847 to 1878, and 

 clover from 1883 to 1885. After 1885 the field was untouched. In 

 June 1903 this field contained practically no leguminous Vegetation, 

 but bore 86 per cent. of a particular grass, Aira caespitosa. 



The most interesting result recorded in the paper lies in the 

 remarkable increase in the amount of nitrogen contained in the soil. 

 This increase amounted in the case of the first field to 100 Ibs. per 

 acre per year for 22 years, and in the case of the second field to 

 somewhat less. 



Neither the action of leguminous plants nor of soil bacteria, nor 

 the additions brought by rain are deemed sufficient by the author 

 to account for the increase recorded — even in combination with 

 the two other factors suggested, namely capillary movements of 

 subsoil nitrates, and absorption of atmospheric ammonia by soil and 

 plant. In any event a very remarkable increase in the nitrogen Con- 

 tents of land left fallow is clearly established, and one which it is 

 not easy to account for on ordinary lines. R. H. Lock. 



Hall, A. D., The analysis of the soil by means of the 

 plant. (Journ. agric. Sei. 1905. I. 1. p. 65—68). 



Experiments undertaken to fest the efficiency of the method of 

 ash analysis of the plant itself as a means of estimating the require- 

 ments of a given soil for specific manures. 



"The scheme is to take a particular plant grown upon the soil 

 in question, and determine in its ash the proportions of constituents 

 like phosphoric acid and potash. Any deviations from the normal in 

 these proportions may then be taken as indicating deficiency or 

 • excess of the same constituents in the soil and therefore the need 

 or otherwise of specific manuring in that direction". 



