Machines at Work (Classic Reprint)

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Excerpt from Machines at WorkThe 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. Lts 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 sepa rate 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 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.Hammering is another kind of muscle work thatmachines can do quickly and easily. Suppose the water pipes under your street need mending. Repair men have to tear up the pavement in order to reach the pipes. So they bring in jack hammers to do the pound ing. Strong blasts of air run the hammers, and, in no time, the pavement is broken up.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.