(113) 



Pounda. 



Siliceous sand 111.3 



Calcareous sand , 113.6 



Sandy clay 97.8 



Loamy clay , 88.8 



Stiff clay 80.3 



Slaty marl 112. 



Fertile mould 68.7 



Common arable soil 84.5 



Chemists, from the earliest times, have been struck with 

 the great proportion of insoluble to soluble substances in 

 the soil. These insoluble substances will resist the action 

 of acid and alkali in any quantities short of destroying 

 vegetation. Analysts have striven by the aid of weak 

 solutions of acids and alkalies to effect this, and though the 

 science is by no means perfect, they have succeeded in ren- 

 dering much inert matter, that has hitherto cumbered the 

 land, into plant food. In an average of many kinds of soil 

 the proportions are, of 



Insoluble matters 89.305 



Soluble matters 2.047 



Phosphate, carbon, and sulphate lime 3.160 



Thus it is seen that of the great mass of soil, ranging 

 from a few inches to many hundred feet thick, only a very 

 small per cent, is available to vegetation. Further, chemical 

 analysis has also developed the fact that all animal tissues 

 are composed of these identical elements of the soil. Truly 

 and literally we are made of dust. But the animal king- 

 dom does not derive its sustenance directly from the soil 

 that would be impossible. Our digestive organs are not 

 constructed for that purpose, and could not assimilate such 

 food, though in the great famine of Germany, in the 18th 

 century, the starving millions did essay it only to die in tor- 

 ture. Nature has provided an intermediate agent, vegeta- 

 tion, whose organs are nicely adapted to this purpose. They 

 send down into the soil their sensitive feelers, and pick up 

 such stray bits of food as men or beasts require. They 

 store it away in their granaries until it is called for, and 

 8 



