el.
1871, Dec. 12 Total eclipse visible in India. Janssen observes
reflected Fraunhofer lines in spectrum of corona.
1872 Conclusion of a three years' series of observations on
lunar heat by Lord Rosse.
1872 Spectrum of Vega photographed by H. Draper.
1872 Faye's cyclonic hypothesis of sun-spots.
1872 Young's solar-spectroscopic observations at Mount
Sherman.
1872 Cornu's experiments on the velocity of light.
1872, Nov. 27 Meteoric shower connected with Biela's comet.
1873 Determination of mean density of the earth by
Cornu and Baille.
1873 Solar photographic work begun at Greenwich.
1873 Erection of 26-inch Washington refractor.
1874 Light-equation redetermined by Glasenapp.
1874 Vogel's classification of stellar spectra.
1874, Dec. 8 Transit of Venus.
1876 Publication of Neison's _The Moon_.
1876, Nov. 24 New star in Cygnus discovered by Schmidt.
1876 Spectrum of Vega photographed by Huggins. First
use of dry gelatine plates in celestial photography.
1877, May 19 Klein observes a supposed new lunar crater (Hyginus N.).
1877 Measurement by Vogel of selective absorption in solar
atmosphere.
1877, Aug. 16-17 Discovery of two satellites of Mars by Hall at
Washington.
1877, Sept. 23 Death of Leverrier.
1877 Canals of Mars discovered by Schiaparelli.
1877 Opposition of Mars observed by Gill at Ascension.
Solar parallax deduced = 8.78".
1878, January Stationary meteor-radiants described by Denning.
1878 Publication of Schmidt's
_Charte der Gebirge des Mondes_.
1878 First observations of Great Red Spot on Jupiter.
1878 Conclusion of Newcomb's researches on the lunar theory.
1878, May 6 Transit of Mercury.
1878 Foundation of Selenographical Society.
1878, July 29 Total eclipse visible in America. Vast equatoreal
extension of the corona.
1878, October Completion of Potsdam Astrophysical Observatory.
1878, Dec. 12 Lockyer's theory of celestial dissociation communicated
to the R