Charlie could play tricks with the motor grader’s front wheels, too. Besides steering them in the ordinary way, he often made them lean over toward the right or the left. To look at them, you’d think they were broken, but they were only tilting to do a special job. They were actually in a tug-of-war with the blade and the earth it was pushing. The weight of the earth against the blade pulled the grader toward one side. But the leaning of the wheels pulled in the opposite direction. So the two pulls balanced each other. Charlie could guide the grader in a straight line without having a wrestling match with his steering wheel. [Illustration] Charlie leaned his wheels when the grader went around a bend in the road, too. They helped the long machine to turn easily. If he had to back into a ditch, [Illustration] [Illustration] he didn’t worry. The great wheels adjusted themselves to the sloping earth. All six wheels stayed on the ground, and the machine never got hung up the way a four-wheeled automobile would. [Illustration] When the earth had been smoothed down, it was time to put the hard surface on. Trucks brought in crushed rock to make a solid bed. Concrete mixers covered the rock with concrete. And asphalt spreaders put a coat of asphalt on top. Wherever the asphalt wasn’t spread evenly, men with rakes finished the job by hand. Then came the tandem roller to pack it down and make the surface smooth. A Diesel engine moved the roller’s great weight quickly back and forth over the asphalt. In no time the road was as smooth as a table top. If the driver wanted to, he could turn his seat sideways. Then he could easily see whether he was guiding the roller straight forward and straight back. [Illustration] Many people call road rollers “steam rollers.” That’s because the first ones really were driven by steam engines. Men have a lot less fuss and bother with a modern Diesel-engined tandem. There’s no need to start the fire or shovel coal to keep steam up. You can still see some steam rollers at work, though, because they are strong machines that last a long time. But when one wears out, it is replaced with a modern roller. After the roller finished smoothing all the asphalt down, Charlie’s road was ready for traffic, but the job still wasn’t quite done. All along the highway the machines had left bare banks of earth. These had to be protected from the weather--just the way a house is protected with a coat of paint. The best coat for the earth is grass of one kind or another. So Charlie turned gardener. In some places he used the motor grader again to prepare the soil so that seed could be planted. With the blade of his grader hung away out at the side and pointed up in the air, he smoothed off the steep banks. Running along the edge of the road, he filled in the soft shoulders. [Illustration]