MAN-MADE GIANTS
You could do everything that the machines in this book do. For some of the jobs, of course, you’d have to get friends to help you. But people have always been able to work and build wonderful things, using just their muscles. And they can do a very great deal more when they use their brains, too. They can invent machines to make work thousands of times easier and faster.
The big machine in the picture is a shovel that’s used for digging an enormous hole. In one bite, its scoop can tear out a chunk of earth more than twice as tall as a man. Its long arm, called the boom, lifts the load as high as the top of a seven story building, then swings around and drops it almost a city block away.
There are only a few shovels like this in the world. They were especially made to work where beds of coal lie close to the surface of the earth, covered by a layer of soil. The shovels clear away the soil so that other machines can dig out the coal.
When a giant shovel has cleared off one spot, its crawlers begin to turn, and it creeps slowly ahead. But it can’t travel on roads. It’s far too big and heavy and tall—so big, in fact, that it came to the mine in separate pieces. Forty-five freight cars were needed to haul all the parts for just one machine from the factory to the mine. Then experts put the parts together right where the shovel was to start digging.
And dig it does. In one minute its scoop can bite out as much dirt as 3,600 men could dig just using their muscles to lift ordinary hand shovels!
The giant shovel is one of the biggest machines ever made, but there’s another that can lift even bulkier things. It is an overhead crane that works in a shipyard.
Often the crane hoists big boilers out of ships so that repair men can work on them. It is so huge that it carries another crane on its back. The piggy-back crane—that’s its real name—reaches down and lifts things off the deck of the ship, too.
