In Chicago in 1889, the Charter Gas Engine Company experimented with a tractor design by mounting a single cylinder petrol engine onto the chassis of an old steam engine. At this time there were many other companies producing their own `prototype' machines and by the beginning of the 19th century a number of these machine were being produced.
Over the next few decades many new tractors were developed. The Ford Motor Company and the International Harvester Company in the US designed two of the most popular machines. As tractors became more versatile they were accepted as a very necessary part of farming, particularly after Harry Ferguson added a hydraulically controlled implement which could be mounted onto the back of the tractor, this plough or cultivator is now a modern day feature on tractors.
The tractor is mainly used for its great pulling power, rather than its speed, so it has to be both rugged and strong. The power is necessary when it is applied to tasks such as dragging large weighty ploughs through heavy soil. The most common form of tractor has enormous wheels at the rear with wide treads, and smaller wheels at the front. When extra grip is required, for instance in waterlogged areas of ground, crawler tracks can sometimes be fitted in their place. Many tractors use diesel engines similar to the ones used in trucks.
The tractor has become the workhorse of the modern farm due to its extraordinary versatility. The range of implements which can be hooked up to a tractor include ploughs, harvesters, tillers and grain drills.
