Mechanization in 1801, displacing the centuries-old hand method of making individual sheets of paper. One of the first mechanical devices used in agriculture was the seed drill invented by Jethro Tull around 1700. The seed drill allowed more uniform spacing of seed and planting depth than hand methods, increasing yields and saving valuable seed. Mechanized agriculture greatly increased in the late eighteenth and early nineteenth centuries with horse drawn reapers and horse powered threshing machines. By the late nineteenth century steam power was applied to threshing and steam tractors appeared. Internal combustion began being used for tractors in the early twentieth
Drill instructor Drill Instructor Ribbon, and the Army's Drill Sergeant Identification Badge. It may be taken offensively by U.S. Marine Corps Drill Instructors to be referred to as 'Drill Sergeants', which is strictly an Army term in the American military, just as Marines may take offense to being called "soldiers". This is considered to be a grievous insult if done intentionally. The only acceptable address of a drill instructor by a recruit is "sir", "ma'am" or "(senior) drill instructor (Rank) (last name)". At Officer Candidates School (OCS), candidates are instructed by Drill Instructors who have already served a tour at one of