202 THE EARTH MADE READY FOR MAN 



As you have already learned, the underground 

 water is like the servant that brings treasures to 

 the store-room and packs them away so nicely, 

 while the surface water is like the servant that 

 opens the storehouse and distributes the treasures 

 for people to use. 



See if you can tell what use we make of some of 

 these minerals: gold, silver, copper, lead, iron, 

 platinum, sulphur, salt, tin, aluminum, mercury, 

 zinc and nickel. There are so many more that it 

 would take a large book to tell about them. Some 

 are individual minerals like the gold and silver, 

 some are joined together like the iron and sulphur 

 in the little yellow cubes, and like the sodium and 

 chlorine which make common salt. 



Some of these minerals we might do without. 

 The metals, as we call gold, silver, lead and zinc, 

 are not necessary for life. The first people who 

 lived never had them. But salt and iron, in some 

 form which can be taken up by growing things, 

 are absolutely necessary to the life of man and 

 animals alike, and even plants seem to need them 

 too. 



We could live, though we should still be uncivilized 

 people, perhaps even savages, if we had not found 

 and learned to use metals like iron, gold and silver. 

 But we could not live at all, neither could the 

 animals or the plants, if the rain water in sinking 

 down did not free those invisible particles of iron 

 and sodium and potash and the other mineral salts, 

 as we call them, and carry them to the searching 

 rootlets of the plants, 



