THE SOIL OF THK KAKM. 



modifying the texture of land. Without it a soil would be light in colour 

 powdery, dry, and harsh to the touch. With it it becomes brown in colour, 

 cool, moist, and mellow, and in every way better fittad for the growth of 

 plants. 



MINERAL Fi: s (STONES). Although stones might at first sight 



appear rather as intruders than as legitimate constituents of a soil, their 

 constant occurrence and important uses lead us to consider them in the 

 latter light. Their precise nature will depend upon the origin of the soil. 

 Thus in an alluvial deposit or drifted soil we expect to find water-worn 

 round pebbles ; in an oolitic limestone, irregular fragments ploughed up 

 from the rock beneath, and in a chalk soil we expect to find flints. Tln-y 

 always modify the character of land when they occur in large nu mi- 

 Many soils now worked as light land would be unworkable clays were 

 they not lightened up and divided by countless stones. It is also im- 

 portant to bear in mind that stones may be regarded as undecayed frag- 

 ments of the original rock from which the soil itself was derived. They 

 >f all sixes, down to minute chips and particles, and especially must 

 these smaller particles yield up fresh mineral food for plants under the in- 

 fluences of frost, warmth, and moisture. A time must come in which even 

 the largest will crumble down, and hence we may regard the mineral 

 fragments as a magazine of mineral plant food. 



A soil is then no mere mass of powdered rock, but a complex substance, 

 the product of various forces, acting through long cycles, and modified by 

 the growth of plants, and the decay of both vegetable and animal matter. 

 Soils may be spoken of as the graveyard of countless generations of ani- 

 matril nature ; as stocked with plant food at once available, and fortified 

 with further as yet unprepared material, forthcoming when required. 

 In til-- language of a respected authority, it may be spoken of as a 



in which beneficial changes are ever taking place, a vehicle by 

 which plant food finds its way to the root fibres of growing v.-getation, 

 and a st<n'<-/i<ni8e of present and future plant food. 



1 properties of soils will be modified according to the propor- 

 ifl in \vhl clay, lime, vegetable matters, and niin.-rul tVa^m 



enter into their composition. 



to possess frrtility in the highest degree, a soil must atVonleasy 

 access and egreefl t Miprrtluous water, but at the sain.' tiim- must possess 

 sui:' ive power to guard against protracted drough t tare 



must be at once firm and yielding, so as to aflord protection to ror 

 while it allows of their free passage in search of nutriment ; it should be 



