On the Effect Produced on the Deviations of the Compass by the Length and Arrangement of the Compass-Needles; and on a New Mode of Correcting the Quadrantal Deviation

A. Smith, F. J. Evans
1861 Philosophical Transactions of the Royal Society of London  
doi:10.1098/rstl.1861.0010 fatcat:xstu3ogcejfmrhbebnyqwbrksu