This Duncan single-furrow plough was one of the earliest iron ploughs to be manufactured. The plough was pulled by one or more horses and controlled by a person walking behind. They used the steering rod to turn the steering wheel and vary the furrow width if necessary, then lifted the plough out of the soil at the end of each furrow, and dropped it after turning around to start the next. The turning coulter wheel cut through the soil, and the ploughshare lifted a neatly cut furrow, which was turned by the mouldboard and laid over the previous furrow.