26 



THE ELEMENTS AND THE SOIL 



greater the proportion of oxygen and hydrogen, because the proportion 

 of water is greater. 



Ultimate composition of a wheat plant at maturity, containing 10 per cent mois- 

 ture. The hydrogen and oxygen of the water are included in the statement 



Carbon 

 Hydrogen 



42.87 

 6.04 



Oxygen 45.26 



Nitrogen 

 Potassium .... 

 Calcium .... 

 Phosphorus . . . 

 Other ash constituents 



0.94 

 0.36 

 0.33 

 0.11 

 4.09 

 100.00 



Ultimate composition of human body. The proportion of C varies greatly with the 

 amount of fat, also the and ash to a less extent. The statement includes the 

 oxygen and hydrogen of the water 



The water is about 65 per cent, which makes the dry-matter in the 

 animal much less than in the mature plant, the moisture content of 

 which is shown to be 10 per cent in the preceding table. 



The Ash and Mineral Parts of Animals and Plants 



When a plant is oven-dried, the free or uncombined water passes off. 

 When it is completely burned, the carbon, hydrogen, nitrogen and most 

 of the oxygen are driven off. What remains is ash, containing the mineral 

 elements. Incomplete burning of plant material results in coals and 

 ash ; the coal is mostly carboiL Charcoal is carbon. 



