On the effects produced in the rates of chronometers by the proximity of masses of iron

• Published in: Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1833
• Subjects: Arctic; Barlow
• Online Access: http://dx.doi.org/10.1098/rspl.1815.0160; https://royalsocietypublishing.org/doi/pdf/10.1098/rspl.1815.0160

It having been ascertained that during Captain Buchan’s voy­age to the arctic regions, in 1818, the rates of chronometers dif­fered on board and on shore, and this change having been attributed by Mr. Fisher to the iron of the vessel, the author felt desirous of examining into the effects of the proximity of masses of iron upon chronometers’ rates, and of determining their causes. In this communication he details the results of a variety of experiments and observations relative to the effects of iron on chronometers placed under different circumstances in its vicinity; whence he concludes, that it undoubtedly does alter their rates, but that it does not necessarily accelerate them, as suggested by Mr. Fisher; on the contrary, in Mr. Barlow’s experiments, it was generally productive of retardation, much depending upon the direction of the balance in respect to the iron; and although the law of this influence has not been ascertained, it is suggested as a practical conclusion, that on ship-board care should be taken to keep chronometers out of the vicinity of any considerable mass or surface of iron; and as much of the iron of a ship is concealed, Mr. Barlow thinks the best way of ascertaining the best situation for a chronometer would be to set down a compass in any place designed for it, and to observe and compare the direction of a needle with that of the azimuthal compass on deck, while the vessel is on different tacks; and if the disagreement between the two be very considerable, another place should be chosen. Lastly, as the power of the iron to disturb the chronometer resides on the surface (as in the instance of the compass), and as we know generally the distance and direction of a plate, such that its power may be equal to the mean action of the iron of the vessel, we are thence able to ascertain, before a chronometer is sent on board, whether the effect of the ship’s iron will be to accelerate or retard its going.