Correspondence, calculations and observations concerning the correction of compasses on iron ships. The correspondents include W.H. Smyth, E. Sabine, W. Scoresby, F.J.O. Evans and J. Washington. The papers include a questionnaire from the Liverpool Compass Committee; a circular advertising the compass bearings of Vauxhall Chimney, Liverpool, as painted on the dock walls, and a map relating the bearings to the buildings along the river; a newspaper cutting and a circular on W. Scoresby's compass experiments on board the 'Royal Charter'; two diagrams extracted from the First Report of the Liverpool Compass Committee; pages from 'The Athenaeum' of 10 and 17 March 1855 containing a two-part paper by W. Scoresby on rapid changes in the magnetism of iron ships; a paper by W. Scoresby titled 'Illustrations of the Magnetism of Iron Ships'; a paper by A. Smith on deviations of the compass on iron ships; a plan showing 'Lines of no deviation on hull of SS Fiery Cross', sent to Airy by T.B. White; a circular advertising 'Gray's Floating Compass'; two circulars advertising 'Smalls Patent Mariner's Compass'; a paper titled 'Review of the correspondence between Dr Scoresby and Professor Airy on Deviations of the Compass and the best means of rectifying them by Paul Cameron'; circulars from F. Wiggins advertising his abilities as a compass adjuster; a copy of the 'Instructions for the Management of the Binnacle Compasses in HMS 'Trident' as corrected by Mr John Gray, for the guidance of the Officer charged with care of the Compasses'; and several circulars on compass errors, their detection and causes.