Nobody could possibly do by hand all of the spraying that protects farmers’ crops. Mechanical sprayers come in many shapes and sizes. The most usual sort for big fields travels along behind a tractor, shooting chemicals out from nozzles in a pipe that is twenty or thirty or even sixty feet wide.

Some of the special sprayers are queer looking machines. One of them has six squirmy arms, bent in different directions so that they get the chemicals underneath leaves and on top as well. The kind that sprays fruit trees pumps chemicals out of twelve pipes at once. It works so hard and fast that farmers call it a cyclone.

Then there is a sprayer that can be used for several different kinds of job. One day the farmer hitches it up to a tank near cattle pens. As the cattle walk down a narrow path between two fences, he sprays them with a chemical that kills bothersome insects. Next day, he may want to paint his fence. So he rigs the machine up differently and shoots paint onto the boards.