Unpublished paper, 'On the application of the law of the conservation of energy to the determination of the magnetic meridian on board ship; when out of reach or out of sight of land' by William John Macquorn Rankine Rankine states that, assuming that when a ship is swung completely round, so that her head bears exactly as it did at first, the magnetism of the ship, and that of the compass-needle return to their original condition, the following theorem is necessarily true: the mechanical power developed by the mutual action of the ship and of the compass-needle during a complete revolution of the ship is equal to zero. Annotations in pencil throughout. Subject: Physics / Marine engineering Received 5 April 1853. Communicated by Col [Edward] Sabine. Written by Rankine in Glasgow [Scotland]. Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 6 of Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London [later Proceedings of the Royal Society] as 'On the application of the law of the conservation of energy to the determination of the magnetic meridian on board ship, when out of reach or out of sight of land'. 2 April 1853