Jethro Tull's four-coultered plough, 1733.
© Science Museum / Science & Society Picture Library
Illustrated plate (page 192) taken from 'The horse-hoing husbandry' (2nd Edition, London, 1743) by Jethro Tull (1674-1741), showing his four-coultered plough. A coulter is the part of a seed drill that makes a furrow in the land into which the seed is sown. Tull began his investigations into scientific methods of seed cultivation in the late 1600s. In around 1701 he produced his first drill to make channels, drill and cover the seed. A grooved cylinder rotated against a spring-held tongue, received the seed from the seed-box and dropped it evenly.