been prepared showing the distribution of fruit in the counties of 

 Kent, Surrey and Sussex, on which the acreage in each parish was 

 indicated by a series of black dots, thus forming together a shading 

 showing the density of plantation. Such a map considered alongside 

 a geological map of the same district, at once showed that the 

 fruit was congregated on certain formations and absent from others. 

 Similar maps showing the distribution of hops, turnips, barley etc., 

 revealed a simular correlation between the crop, the geological for- 

 mation and the structure of the soil as determined by mechanical 

 analysis. In deciding upon the kind of soil required by a plant 

 empirical methods alone can be followed ; it is impossible to decide 

 a priori what the requirements of the plant will be. 



But though the mechanical composition of soils reveal the chief 

 factor in the association of plant and soil, one or two chemical 

 factors of importance can be discerned. A distinction must be 

 made between acid and non-acid soil, the acid soils being gene- 

 rally recognizable in nature by the tendency of peat to accumulate 

 upon them. It is problable that the plants themselves are indifferent 

 to any acidity ofUhe soil water from which they are drawing nutri- 

 tion ; but in an acid medium the action of bacteria is generally sus- 

 pended, nitrification ceases, and the soil becomes wholly permeated 

 by the mycelium of various moulds and other microfungi. 



The other factor of importance is the amount of carbonate of 

 lime in the soil, but a distinction must be drawn between the cases 

 in which carbonate of lime acts merely as maintaining a neutral 

 reaction, and those in which it acts positively and is of direct 

 benefit to certain plants. Carbonate of lime is regarded as poiso- 

 nous to certain plants, e. g. Erica and Rhododendron; but this is 

 probably not a positive injurious action of the lime on the plant, 

 but a secondary one, in that the lime removes the acid soil conditions 

 which these plants find necessary. , 



In the present state of our knowledge it is vanity to dogmatise 

 about the requirements in th6 way of soil of more than a very few 

 plants. 



A. D. HALL. Old and New Studies on Fertility. -- Nature, 

 n. 2132. Vol. 84, September, 8, 1910, p. 310. The British Ass. 

 for the Adv. of Science, Sheffield Meeting. Opening Address 

 of the Chairman of the Agricultural Sub-section of B (Chemistry). 



" In a paper published in the Philosophical Transactions in 1845, 

 being the Bakerian Lecture for that year, Daubeny described a 

 long series of experiments that he had carried out in the Botanic 



