| Description | Tables of magnetic declinations recorded at five minute intervals, twelve observations per hour, from 10.00pm on 18 March to 10.00am on 19 March 1840.
The Royal Society's interest in magnetic observations at this period was in response to a letter by Alexander von Humboldt, 23 April 1836, to William Parsons, 3rd Earl of Rosse and President of the Royal Society, proposing an international network of observatories [AP/20/7].
Headed [p.1]: 'Observations de la déclinaisons magnetique...'. With a note [p.3]: ''Les observateurs étaient MM. Mailly et Bouvy, aidez de l'observatoir Liagre et Marneffe officiers ingenieure et Quetelet [The observers were MM. Mailly and Bouvy, with help from the Liagre observatory, Marneffe engineering officers, and Quetelet]. Endorsed [p.4]: 'Magnetic observations [Gottingen - scored through] Bruxelles [in pencil] in 1840'. Typed paper label: 'Brussels. 1840.'. |