Engraving showing seaman on board the P.&O. steamship, 'Malwa', en route from Britain to India heaving the log from the stern of the ship. By tossing a log over the stern of a ship, with a long line attached, one could work out the speed of the vessel by seeing how much line went overboard during a given time. In the middle of the image a seaman is holding up a sand timer, whilst on the right the ship's wheel can be seen.