90 



BRITISH PLANTS 



Comparison between the Physical Properties of Sand and 



Clay. 



Clay. 



1. Particles small. 



2. Individual air-spaces small ; 

 total pore- space large. 



3. Cohesion great. 



4. Soft and greasy to the touch 

 when wet. 



5. Maximum water - capacity 

 great, 



6. Amount of hygroscopic water 

 great, 



7. Water - retaining capacity 

 great. 



8. Almost impermeable to 

 water. 



9. Capillarity great, 



10. A wet soil. 



11. A cold soil. 



12. When dry, is hard and 

 cracks. 



13. Drainage difficult. 



14. A fertile soil, since it is diffi- 

 cult to wash soluble matter out 

 of it. 



15. A heavy soil, hard and ex- 

 pensive to work. 



Chalky soils occupy an intermediate position in some 

 characters more approaching sand, in others clay. The 

 best soil is that which, while light and warm, is fertile in 

 plant-food, and contains plenty of water, without appear- 

 ing wet. No one of the above soils fulfils all these con- 

 ditions, but by suitably mixing sand, clay, and chalk 

 together a loam is obtained which answers most of these 

 qualifications fairly well. 



Sand. 



1. Particles large. 



2. Individual air-spaces large ; 

 total pore-space small. 



3. Cohesion of the particles very 

 small. 



4. Firm and gritty to the touch. 



5. Maximum water - capacity 

 small. 



6. Amount of hygroscopic water 

 small. 



7. Water - retaining capacity 

 small. 



8. Very permeable to water. 



9. Capillarity small. 



10. A dry soil. 



11. A warm soil. 



12. When dry, is friable anfl 

 does not crack. 



13. Drainage natural and easy. 



14. A sterile soil, since soluble 

 matter is easily washed out of it, 



15. A light soil, easy to work. 



