| Description | Roberts aims to produce an instrument that could, under all variety of circumstances, give a correct (magnetic) meridian direction, or in some way indicate the amount of its own error. He considers that he has, at least partially, succeeded in the attainment of this object in the instrument described in this paper. In order to determine the nature of the action of a mass of iron on a magnetic needle, Roberts constructed needles with the magnetic bar wholly on one side of the central support, counterpoised by an arm carrying a weight on the other.
Annotations in pencil throughout from S H C [Samuel Hunter Christie]. Note on front reads 'Accompanied with two instruments'. Includes four plates in coloured ink of Roberts' instruments.
Subject: Marine engineering / Magnetism / Scientific apparatus and instruments
Received 25 March 1852. Read 18 June 1852. Communicated by Captain [William Henry] Smyth.
Written by Roberts in Portsmouth [England].
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 'Experiments towards the construction of new forms of instruments for the correction of compass errors due to the presence of iron in ships; with investigations on the nature of the attraction of iron on the poles of magnets'. |