CLAYEY LANDS. 77 



faculty of maintaining or permitting the escape of 

 moisture. 



." Generally, clayey lands answer better in dry 

 climates, and light sandy soils in countries where 

 rains are frequent. Kirwan made this remark long 

 ago with reference to the analysis of wheat lands. 

 The conclusion to which this celebrated chemist 

 came was, that the soil best adapted for wheat in a 

 rainy country must be of a different composition 

 from that required where rains were less frequent. 

 The fertility of sandy soils is notoriously in intimate 

 relationship with the frequent fall of rain. Sandy 

 deserts are sterile because it never rains. Upon 

 the sandy downs of the coast of the Southern Ocean 

 a brilliant vegetation is seen along the course of 

 the few rivers which traverse them; all beyond is 

 dust and sterility. A sandy and little coherent soil 

 is by so much the more favorably situated as it lies in 

 the least elevated parts of a district, since it is there 

 less exposed to the effects of drought. Any consid- 

 erable degree of inclination is unfavorable to such 

 a soil, inasmuch as the rain drains off too quickly, 

 and because it is itself apt to be washed away. It 

 is to prevent this action of the drains that the 

 abrupt slopes of hills are generally left covered with 

 trees ; and the deplorable consequences which have 

 followed from cutting down the wood in mountain- 

 ous countries are familiarly known. 



" Strong soils, on the contrary, are better if thus 



17* 



