Jethro Tull invented some machinery for the purpose of carrying out his system of drill husbandry, about 1733. His first invention was a drill-plough to sow wheat and turnip seed in drills, three rows at a time. There were two boxes for the seed, and these, with the coulters, were placed one set behind the other, so that two sorts of seed might be sown at the same time. A harrow to cover in the seed was attached behind.