88 BOARD OF AGRICULTURE. 



the various forms of food are rendered assimilable. It is the 

 liquid medium which holds all the inorganic substances, and 

 from the aqueous current which unceasingly flows through the 

 little cells of plants, they are absorbed and appropriated as food. 



Enormous quantities of water annually descend upon the 

 land. If the rain-fall be but twenty inches per annum, it 

 corresponds to something like two thousand and twenty tons 

 of* water falling upon each acre every year. Much of this is 

 carried off by evaporation or through drainage. Still a large 

 proportion is retained by growing plants or passes through them, 

 aiding in most important functions. It can be shown that a , 

 gallon of water passes through a single plant of wheat in a 

 season, and the aqueous exhalations from the broad disc of a 

 common sunflower each day amount to six or eight ounces. 



The wonderful substance (formerly rare and costly), phos- 

 phorus, is so essential an ingredient in the food of plants that 

 not one of any kind can flourish without it. This highly com- 

 bustible body, so offensive to taste and smell, and withal so 

 poisonous, enters the plant in combination with oxygen, with 

 which it forms phosphoric acid. The entire supply of phospho- 

 rus employed in the arts comes from plants, and they hunt it 

 from the soil atom by atom, and incorporate it into their struc- 

 tures. Animals feeding upon plants abstract the element, and 

 it takes its place in the bones in combination with lime, form- 

 ing basic phosphate of lime. We gather the bones of the dead 

 animals, and, after calcination, subject them to chemical treat- 

 ment, and thus isolate the phosphorus in a pure state in large 

 quantities. How curious is this cycle of changes and trans- 

 formations ! "We can in no way obtain a clearer conception of 

 them than by reflecting upon the fact that the phosphorus found 

 upon the end of every friction match we use in our dwellings 

 has been gathered from the soil by vegetables, and passing 

 through their organization it has taken its place in the bones 

 of oxen, cows or horses, and from thence passed into the labora- 

 tory of the chemist, where it is fitted to subserve the most useful 

 purposes. If this substance had a tongue, what an interesting 

 history of adventures it could unfold ! 



The amount of phosphorus or phosphoric acid in the soil is 

 usually insufficient to meet the wants of the plant, and hence 

 the farmer must furnish supplies if he wishes to increase his 



