Authorised form of nameJanssen; Pierre Jules Cesar (1824 - 1907)
Dates1824 - 1907
Place of birthParis, France
Date of birth22 February 1824
Place of deathMeudon, France
Date of death23/12/1907
Research fieldPhysical astronomy; spectroscopy; photography
Teacher, Lycee Charlemagne, Paris (1853); travelled to Peru to determine the magnetic equator (1857); Teacher, School of Architecture, Paris (1865-1871); made magnetic observations in the Azores (1867) and at Oran, Algeria (1882); observed solar eclipses in Algiers, for which he escaped from Paris in a hot air balloon (1870), Siam (1875), Caroline Islands (1883) and Spain (1905); Director, Astrophysical Observatory established by the French government, Meudon (1875)
Membership categoryForeign Member
Date of election08/04/1875
Royal Society activityMedals and prizes:
Rumford Medal 1876
Bulloch's Roll; DSB
Proc Roy Soc Series A 1908 vol 81 pp lxxvii-lxxxi signed by N L
Virtual International Authority File
Royal Society codeNA6526
Archives associated with this Fellow
Reference numberTitleDate
MC/8Volume 8 of miscellaneous correspondence regarding business matters, sent to the Royal Society1867-1869
EC/1875/09Janssen, Pierre Jules Cesar: certificate of election to the Royal Society
M/103Janssen, Pierre J C, and J Norman Lockyer18 August 1868
NLB/11/1016Copy letter from Michael Foster, to Monsieur Professor Pierre Jules Cesar Janssen[November 1895]
NLB/9/269Copy letter from Herbert Rix, to Professor Joseph Norman Lockyer, Fellow of the Royal Society24 April 1894
NLB/9/244Copy letter from Herbert Rix, to Professor Joseph Norman Lockyer, Fellow of the Royal Society20 April 1894
NLB/9/272Copy letter from Lord Rayleigh [John William Strutt], to Monsieur Pierre Jules Cesar Janssen, Foreign Member of the Royal Society, Observatoire de Meudon, Seine et Cise, France[24 April 1894]
NLB/19/55Copy letter from Theodore E James, to Messrs Harrison & Sons8 June 1899
NLB/11/999Copy letter from Michael Foster, to Monsieur Pierre Jules Cesar Janssen, Foreign Member of the Royal Society, Observatoire de Paris14 November 1895
NLB/36/856Copy letter from Robert William Frederick Harrison, to Messrs Harrison & Sons3 January 1908
NLB/36/827Copy letter from Joseph Larmor, to the family of Pierre Jules Cesar Janssen and the authorities of the Observatory of Mendon24 December 1907
MS/427/260Copy letter from [William] Spottiswoode, President of the Royal Society; to Mr. [Pierre] Jules [Cesar] Janssen (Foreign Member, FRS)17 February 1883
NLB/22/613Copy letter from Sir Michael Foster, to M Le Professeur [Jules] Janssen12 June 1901
MC/8/292Letter from [Pierre Jules Cesar] Janssen, Simla, Himalaya, to W [Warren] de la Rue2 January 1869
MC/8/311Letter from Warren de la Rue, 139 Marina Parade, Brighton, to Professor [George Gabriel] Stokes, Secretary of the Royal Society2 February 1869
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