122 PRINCIPLES OF CtARDENING. [cH. II. 



soil is lighter coloured, and although they both rest 

 upon porous subsoils, yet vegetation is always later, 

 and harvest backwarder, on this than upon the other 

 field. So much indeed has colour to do ^vith forwai'd 

 vegetation, that, if the surface of one stetch in a field 

 where wheat is so^^'n be sprinkled thickly with 

 coal ashes, it will be found to be earlier in every 

 stage of growth than the com growing around. This 

 result of obsen-ation is readily explicable upon the 

 fact demonstrated by Leslie and others, that dark 

 surfaces absorb more heat from the sun than light 

 coloured ones. The latter reflect its rays. 



The sensation imparted to the hand when damp 

 portions of various soils are grasped is very ditferent. 

 The greasy feel of the clayey ; the grittiness of the 

 sandy; and the cold softness of the chalky, are 

 easily recognizable by those accustomed to §uch 

 examinations. 



There are two tests connected with handling damp 

 soils that are fer from bad criteria, whereby to judge 

 of their fertility. Let a handful be grasped firmly 

 of each soil under examination, and let each con- 

 solidated handful be placed upon a sheet of paper on 

 a table m the same room, out of the sunshine. The 

 handful which dries first and crumbles do\ra the 

 most easily will be the least fertile. 



Take equal proportions of different equally damp 

 soils, and expose them side by side, each on a 



