swinging the boom, he bashes the skull cracker into the wall of the old building. Over and over, the ball strikes the mortar and bricks. Cracks spread, and big chunks of the wall start tumbling to the ground. In a little while Charlie and his machine have made a heap of rubble out of a house that it took dozens of men to put up.
BUILDING A ROAD
Once Charlie worked on a road-building job. There he used a crane and a shovel and many other machines besides. This particular road had to cross a big swamp near the ocean. So the first problem was to fill up the swamp with something solid. In order to get enough earth and rock for the fill, men would have had to tear down a whole mountain. Instead they called in suction dredge machinery for the job. The huge pumps sucked sand from the bottom of the sea and poured it through pipes onto the swampy ground. When the water drained away, millions of tons of fine white sand were left.
Charlie helped level the sand off with a bulldozer. Then he moved on to a place where a hilly spot had to be leveled. There he drove a carrying scraper, a machine with a scoop between its front wheels and its rear wheels. The sharp scoop scraped up a load of earth, and Charlie drove off to dump it in a low spot. When he got there, a pusher blade at the back of the scoop pushed the earth out. Round and round he went, without having to stop for loading or unloading.
Other men used a different machine like the one in the picture. This earth mover carried more in one load than the motor scraper, and it was better for hauling earth longer distances. For very short hauls, Charlie drove a fast little tractor. At least it looked small compared to the giant machines. It pushed a scoop in front of it like a shovel, then lifted a load, turned swiftly and dumped the earth where it was needed a few yards away.
Charlie’s road was going to be a special highway for speedy traffic. In order to make it as safe as possible, the crossroads had to be lifted up over the new highway. Crews of men built these overpasses. First they used the huge earth-moving machines to make little hills on each side of the highway. Then they built bridges of concrete and steel between the hills.
At one place, there were two houses on the exact spot where the hill for an overpass had to be made. Instead of tearing the houses down, moving men just carried them away with the furniture still inside. First they raised the houses off the ground with jacks. Next a tractor backed a wide, low trailer up close to each house. Using special machinery and rollers, the men
