MANURES. 51 



MANURES. 



THE RELATIONS OF ORGANIC TO INORGANIC MATTER. 



Manures are the food of plants. This is a fact which has been 

 well understood through all the ages of agriculture, so far as the 

 mere circumstance of applying them to the soil in order to secure 

 a reasonable crop; but the hoxo they operated to bring this about, 

 or why they were applied at all, have been points not so well com- 

 prehended. That plants are beings of a delicate and complicated 

 organization seems to have been long known, but this knowledge 

 was of a general kind and led to no practical good. It has been 

 left to the science of the present day to unlock this storehouse 

 of exhaustlcss knowledge, and to astonish even the wise men of 

 the nineteenth century with the wonderful developments that are 

 almost daily made of the relations of organic and inorganic mat- 

 ter. A seed falls into the ground, and, watered with the genial 

 showers of spring, soon sends up a tender shoot. It reaches up- 

 ward — expands — throws out its branches and leaves to the light 

 and air, and its roots reach downwards and pierce into the soil. 

 Year after year it grows and spreads till it becomes a tall oak or 

 the gigantic pine. It opens its blossoms and for a few days they 

 rejoice in the glad sunshine and then fade and fall. Next suc- 

 ceeds the fruit — the seed — that strange product which is for the 

 sustenance of the animal world. Whence have the materials been 

 derived, which have served to build up the frame of the plant and 

 perfect its fruit? Have they all come from the soil in which it 

 grew, or from the atmosphere? We prepare the soil and manure 

 it, and sow it with wheat. Does the crop depend upon the soil, 

 the air, or the manure, for sustenance? 



In the early part of the seventeenth century. Van Helmont ad- 

 vanced the theory that water was capable of supplying to plants 

 all they need to perfect their growth, and thought he had demon- 

 strated the truth of his theory by .experiment. In the following 

 century, Jethro Tull maintained that plants only required earthy 

 particles for their nourishment, and that it was only necessary to 

 pulverise the soil to secure an abundant crop. He supposed that 



