THE BRIGHTNESS OF LUNAR ECLIPSES 

 1860-1922 



By WILLARD J. FISHER 



After Struve and Dollen had pointed out the advantages in observ- 

 ing occultations of faint stars during lunar total eclipses, and had 

 circulated data facilitating the observations, there was an interest 

 aroused among professional astronomers, who paid much attention 

 to eclipse occultations for a considerable time ; but only a few, as 

 Flammarion, Barnard, M. Wolf, paid much regard to lunar eclipse 

 phenomena in relation to the earth's atmosphere. The observation 

 and description of the peculiarities of the earth's shadow, both before 

 and after the occupation campaign, was largely left to amateurs. 

 The organization and growth of great societies, like the Societe 

 Astronomique de France and the British Astronomical Association, 

 have greatly increased the number of such observers and the volume 

 of the recorded observations. 



The present paper was undertaken with the expectation that in 

 the mass of lunar eclipse literature there would be found evidence of 

 a structure of the earth's shadow corresponding to the known dust 

 layers of the atmosphere.'' It was found that this object could not 

 immediately be attained ; rather, it seemed desirable first to study 

 the brightness of recorded eclipses. This, to be sure, has been done 

 by A. Danjon,^ in papers in which, from a study of records going 

 back to 1583, he has drawn the conclusion that there is a remarkable 

 relation between the solar cycle and the brightness of lunar eclipses, 

 mostly total. These papers have been destructively criticised by 

 E. W. Maunder,^ as using partial eclipses illegitimately, omitting 

 details of evidence, such as criteria of brightness, durations, moon 

 altitudes, magnitudes of eclipses, together with all references, making 



^ S. P. Langley, New York Tribune, Jan. 2, 1884; Knowledge, 5, pp. 80-81, 

 1884; Sidereal Messenger, 3, pp. 21-23, 1884; Nature, 29, p. 324, 1884; A vast 

 dust envelope. 



W. J. Humphreys, Bull. Mt. Weather Obs., 4, pp. 397-401, 1912; Dust layers in 

 the atmosphere, and changes in the neutral points of sky polarization. 



^A. Danjon, C. R., 171, pp. 1127-1129, 1207-1210, 1920; Bull. Soc. Astr. Fr., 

 35, pp. 261-265, 1921. 



^ E. W. Maunder, Jour. Brit. Astr. Assoc, 31, pp. 346-350, 1921. 



Smithsonian Miscellaneous Collections Vol. 76, No. 9 



