pulls a cultivator or a planter, the driver must turn his head often to see how the work is going. For a long time, farmers complained that this was a pain in the neck, and they really meant that their necks hurt from turning so much. Some of them actually went back to using horses, because they could either walk or sit behind horse-drawn machines. So the farm machine makers had to change as many of the machines as they could, placing them beside the tractor or out in front where the driver can watch what is going on.
Tractors themselves come in many sizes and shapes. Some are built very high off the ground so they can pass over tall crops without hurting the plants. Some have four wheels that can be pushed close together for work in one field and pulled wide apart for work in another. Some have three wheels.
Mostly, farmers buy tractors the way people buy automobiles. They pick a model they happen to like and then argue that it’s the best in the world. Of course, a little light “cub” tractor is easier to handle than a big one, but it can’t do the hard work of a heavy model with huge rear wheels and tires. And here’s something about the tires—farmers often fill them with water instead of air to give them more weight when they grip the ground. In winter, these farmers must put antifreeze not only in the radiator but in the tires as well!
On enormous farms where very heavy work must be done, there are often crawler tractors to do it. Instead of tires they have caterpillar treads that give a better grip on the ground. Then they can pull a whole string of plows the way you see them in the picture, staggered out behind.
This kind of tractor was first named caterpillar by only one manufacturer. But people liked the idea, and they began to call all crawlers caterpillars.
A caterpillar is powerful enough to push a snow plow, too. Or it can bulldoze out a hole for a watering pond or a cellar for a new building.
BUILDING MACHINES
Charlie is the man who can tell you about driving a caterpillar tractor. He works in a city, helping to put up big buildings, and he knows how to use other construction machines, too. In fact, Charlie grew up with machines, for his father and his uncles and his grandfather were construction workers. It often happens that families pass along their knowledge of building from the older to the younger men, and they are very proud of their skills. Charlie uses the caterpillar tractor with a bulldozer blade to push heaps of earth and rock into a pile, ready for the shovel to load on a truck.
