Editing Tractor (section)

=== Traction engines ===
[[File:Harrison Machine Works 1882 tractor.JPG|thumb|left|1882 Harrison Machine Works steam-powered [[traction engine]]]]

The first powered farm implements in the early 19th century were [[portable engine]]s – steam engines on wheels that could be used to drive mechanical farm machinery by way of a flexible belt. [[Richard Trevithick]] designed the first 'semi-portable' [[stationary steam engine]] for agricultural use, known as a "barn engine" in 1812, and it was used to drive a corn threshing machine.<ref name=Hodge>{{cite book|last= Hodge |first= James |title= Richard Trevithick (Lifelines 6) |publisher= Shire Publications |year= 1973 |isbn= 978-0-85263-177-5 |page= 30}}</ref> The truly portable engine was invented in 1839 by [[William Tuxford]] of [[Boston, Lincolnshire]] who started manufacture of an engine built around a locomotive-style boiler with horizontal smoke tubes. A large [[flywheel]] was mounted on the crankshaft, and a stout leather belt was used to transfer the drive to the equipment being driven. In the 1850s, [[John Fowler (agricultural engineer)|John Fowler]] used a Clayton & Shuttleworth portable engine to drive apparatus in the first public demonstrations of the application of cable haulage to cultivation.

In parallel with the early portable engine development, many engineers attempted to make them self-propelled – the fore-runners of the [[traction engine]]. In most cases this was achieved by fitting a sprocket on the end of the crankshaft, and running a chain from this to a larger sprocket on the rear axle. These experiments met with mixed success.<ref name="Lane2">{{cite book|year=1976|isbn=978-0450028373|publisher=New English Library|last= Lane |first= Michael R. |title= Pride of the Road |page= 56}}</ref> The first proper [[traction engine]], in the form recognisable today, was developed in 1859 when British engineer [[Thomas Aveling (engineer)|Thomas Aveling]] modified a [[Clayton & Shuttleworth]] [[portable engine]], which had to be    hauled from job to job by horses, into a self-propelled one. The alteration was made by fitting a long driving chain between the crankshaft and the rear axle.<ref>{{cite book|last= Bonnett |first= Harold |title= Discovering Traction Engines |publisher= Shire Publications Ltd |year= 1975 |pages= 5 |isbn= 978-0-85263-318-2}}</ref>

The first half of the 1860s was a period of great experimentation but by the end of the decade the standard form of the traction engine had evolved and changed little over the next sixty years. It was widely adopted for agricultural use. The first tractors were steam-powered [[ploughing engine|plowing engine]]s. They were used in pairs, placed on either side of a field to haul a plow back and forth between them using a wire cable. In Britain [[Mann's Patent Steam Cart and Wagon Company|Mann's]] and [[Richard Garrett & Sons|Garrett]] developed [[steam tractor]]s for direct ploughing, but the heavy, wet soil of England meant that these designs were less economical than a team of horses. In the [[United States]], where soil conditions permitted, steam tractors were used to direct-haul plows. Steam-powered [[agricultural engine]]s remained in use well into the 20th century until reliable internal combustion engines had been developed.<ref>{{Cite web|url=https://livinghistoryfarm.org/farminginthe30s/machines_04.html|title=Tractors Advance during the Depression|website=livinghistoryfarm.org}}</ref>