| Abstract: | Edmond Halley made two scientific voyages in the Atlantic Ocean as captain of the HMS Paramore between 1698 and 1700. Following these voyages he published the first map showing lines of equal magnetic declination in 1701. Halley did not reveal how he constructed the map, however, and it remains unknown. In this study, a construction procedure is hypothesized that uses mathematical tools that were available in his day, namely arithmetical averages and Isaac Newton’s method of divided difference for fitting a polynomial curve to data. To enable his map construction, a method is suggested whereby Halley could have created new data to augment the situations where insufficient data were collected. |
