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 is evaluated as well. These new drill instructors bear the burden of responsibility for breaking down a recruit's sense of self and selfishness, so that the more experienced drill instructors can focus the recruits on selflessness, obedience, and fraternity. After completing a few 13-week cycles, the drill instructor is moved up to the position of "Experienced Drill Instructor" (EDI), also called the "heavy", "drill hat" or "J Hat". The next step in a drill instructor career is becoming a "Senior Drill Instructor". Senior Drill Instructors hold a respected position which is distinguished by the wearing of a black