Since about 2500 b.c. , draught animals have been used to perform such strenuous tasks as plowing fields and hauling heavy loads. Animals long remained essential for agriculture, road building, logging, and other major industries. It was not until the 1800s that steam-powered road vehicles began to replace animals for heavy work. The work that machines were beginning to perform was not usually done under ideal conditions. Rough or muddy fields and roads often bogged down wheeled vehicles. In 1770 an Englishman, Richard Edgeworth, patented his idea to equip a vehicle with a set of large tracks, which he called an "artificial road." But the idea was never developed. Alvin Orlando Lombard, a farm boy from Springfield, Maine, developed the first hauler with caterpillar treads. Instead of cutting into the surface as conventional wheels do, the treads rode over the surface, using grips to push the vehicle forward...