Modern Business Geography 
raising of beef cattle. We know that forests require a good rain- 
fall and will not grow where the cold is excessive. We even know 
under what conditions sea animals, such as codfish, thrive best. 
With the products of the mines, however, the case is different. 
Since few surface conditions help to explain their distribution under- 
ground, the search for them must often be carried on with relatively 
little guidance from science. Nevertheless the geologist is often able 
to locate ore bodies. Metals are usually found in mountainous regions 
or where mountains previously existed. This is partly because most 
ores are formed far beneath the earth’s surface, where intense heat and 
underground waters cause a concentration of metal-bearing com- 
pounds. Only when mountains are upheaved and worn away by rain 
and rivers are such ores exposed to our sight. But not all mountains 
contain metals. Because the distribution of metals is so irregular, it 
seems almost an accident that the Malay Peninsula and Bolivia produce 
most of the world’s tin; the United States and northwestern Europe, 
most of the world’s zinc ; Mexico and the United States, the silver ;: and 
the United States and Chile, the copper. 
THE MINERAL PRODUCTS 
The treasure that man digs out of the depths of the earth is of 
three kinds — metals, fuels, and stony products. 
The metals. Even in prehistoric times industry and art used the 
chief metals, — iron, gold, silver, copper, tin, lead. and zinc. There 
are many other metals; but only a few are of large commercial im- 
portance ; for example, aluminum, platinum, nickel, cobalt, iridium. 
The fuels. Heat is needed not only for cooking and for warmth, 
but for power and to work the metals. For many centuries it was 
obtained by burning wood. It was not until modern times that 
Europeans discovered that coal can be mined and used for heat, 
light, and power. Still more recently, deposits of petroleum and 
natural gas have been found and utilized. 
Stony products. In the earliest times man used stones as weapons 
and tools. Now he uses stone for buildings, pavements, and many 
other purposes, as well as vast amounts of clay, cement, sand, gravel, 
and other non-metallic minerals. 
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HOW THE MINERAL PRODUCTS ARE OBTAINED 
Metals and coal are mined in nearly the same way, by digging 
holes by which men can go down into the earth, get out what they 
seek, and bring it up to the surface. For petroleum and natural gas, 
deep wells are bored. and the oil or gas is carried off in pipe lines.