220 THE WASTE AND CONSERVATION OF PLANT FOOD. 



originally occurred, and it may not take place until after tlie lapse of 

 thousands of years, but tliis is of no consequence. Provided arable 

 lands in general leceive in some way and at some time a certain return 

 for tbe plant food removed, it is entirely immaterial whether this be 

 the original plant food removed or other equally as good. 



Tlie sea is the great sorting ground into which all this waste material 

 is poured. The roller processes of nature, like the mills of the gods, 

 grind exceedingly slow and small, and the sea becomes the bolting- 

 cloth by which the products of milling are separated and sorted out. 

 As soon as this waste material is ponred into the sea, the process of sort- 

 ing at once begins. Tlie carbonate of lime becomes deposited in vast 

 layers, or by organic life is transformed into immense coral formations 

 or into shells. J'hosphoric acid is likewise sifted out into i)hosi)hatic 

 deposits or ])asses into the organic life of the sea. Even the potash, 

 soluble as it is, becomes collected into mineral aggregates or i)asses 

 into animal or vegetable growth. All these valuable materials are thus 

 conserved and put into a shape in which they may be returned sooner 

 or later to the use of man. In the great cosmic economy there is no 

 such thing as escape from usefulness of any valuable material. 



Sterry Hunt' has called esi)e('ial attention to this sifting and sorting 

 power of water and the important i)art it plays in the formation of 

 crystalline rocks. "Igneous fusion," he says, "destroys the mineral 

 species of the crystalline and brings them back as nearly as j^ossible to 

 the great primary and undifferentiated material. This is the great 

 destroyer and disorganizer of mineral as well as of organic matter. Sub- 

 terranean heat in our time, acting on buried aqueous sediments, destroys 

 carbonates, sulphat* s, and chlorides with the evolution of acidic gases 

 and the generation of basic silicates, and thus repeats in miniature the 

 conditions of the anteneptunian chaos. On the other hand, each mass 

 of cooling igneous rock in contact with water begins anew the form- 

 ative process. The hydrated amorphous product palagonite is, if we 

 may be allowed the expression, a sort of silicated i^rotoplasm, and by 

 its differentiation yields to the solvent action of water the crystalline 

 silicates which are the constituent elements of the crenitic rocks, leav- 

 ing at the same time a more basic residuum abounding in magnesia 

 and iron oxide and soluble not by crenitic but subaerial action." 



Let me call attention, for a few moments, to some of the more impor- 

 tant ways, pointed out through the researches of agricultural chemists, 

 in which these waste products are restored. We are inclined to look 

 upon the sea as devoid of vegetable growth, but the gardens of the sea 

 are no less fully stocked with economic plants than the gardens of the 

 land. The seaweeds of all genera and species are constantly separat- 

 ing valuable materials from the Avaters of the ocean and placing them 

 again in organic form. Many years ago Forchhammer ^ pointed out the 



' Mineral Pbysiology and Physiography, page 188. 

 ^ J. prakt. Chem., 1st series, Vol. 38, page 388. 



