This work, in so far as the mathematical theory of deviations is concerned, is based entirely on the admiralty publication The Theory of the Deviations of the Magnetic Compass prepared by the Admiralty Compass Observatory, Slough, a fact which is greatfully acknowledge.
The book has been written in an endeavour to explain as simply as possible all that is involved in the correction, adjustment and maintenance of magnetic compasses on board ships. With the exception of the Admiralty Manual for the Deviations of the Compass, now out of print, and the above mentioned work written for the Royal Navy, no other book has been published giving the full mathematical basis on which the practical application is based.
