filiii of w.iti-r, which L,'athors round i-arlh-particles, 

 hydroscopic w.ilcr. 1 1 has been ascertained by 

 careful ex|K'riinenl that it i^ onl\- on this fleh'cate 

 uaterx" tihn that the root-h.iirs of phmls arc able to 

 (cc(\. As these hairs drain au'a\' the hy^roscojjic 

 film it is always beiiii;' renewed b\' the free water 

 which comes from rain and dew . The free water 

 of the soil is constant!}' passini;' from the surface to 

 the subsoil, and b\' this action plant-food, in the 

 form of soluble earth salts, is presented to the 

 roots. The passage of the water is of the highest 

 service to the roots, since the warm air follows the 

 water through the soil, and helps to oxidise the 

 mineral particles ; these are thus rendered soluble, 

 and are taken u[j b\- the fine films of water, and 

 so indirectl\- the roots are fed. If, however, there 

 is no outlet for tlic water and the soil becomes 

 water-logged this beneficial action is retarded, and 

 to land-roots the water is hurtful. 



W'e can now understand \\h)- stagnant water 

 in the ground is so injurious to plant-life, as it 

 prevents the needful air from coming int(j contact 

 with the roots, and this is the reason why farmers 

 are careful to remove the surplus water from their 



