318 A WORK TO BE DONE. 



ARABLE LAND. 



A more useful picture than that of the isogeothe^nal lines 

 would be one of all the arable land covering the continents of 

 the Old World and the New, indicating the composition of 

 this nutritive earth, the nature of the soil on which it reposes, 

 as well as the various kinds of cultivation appropriate in 

 different climates. Here is a work to be achieved, a work 

 which would benefit the whole human race, a work differing 

 vastly from the conquests and achievements of too many of 

 those " heroes " the world delights to honour. 



" Peace hath her victories 

 More renowned than war." 



In this immense task, of which, as yet, not even the out- 

 lines have been sketched, particular attention would require 

 to be paid to the subsoil-, for upon this the success of all 

 cultivation literally depends. 



Arable land is the most superficial stratum of the cultivable 



terrestrial crust; it 

 is this which the 



_, , this which, properly 



ric. 09. a, Humus, or stratum of arable earth, the 



horizontal line shows the depth reached by the manured and en- 

 labourer ; b, subsoil; c, subsoil; d, arable earth; 



f, humus in an inclined stratum ; f, humus ncheCl by the de- 

 mixed with subsoil. ,- f 



composition of or- 

 ganic matter, furnishes to vegetables their principal nourish- 

 ment. As it varies in thickness, it necessarily presents 



