62 Eclipses of the Moon. 



over the surface of the moon ten or twenty times beyond the 

 spaces whence the annular mountain may be seen, and it often 

 happens that, when the point has been for long invisible in the 

 obscured portion of the moon, the extremities of the bands may 

 still be distinguished. 



The only conclusion, then, to which we can arrive is, that, by 

 some operation of nature, the interior structure of the lunar 

 soil has experienced, at those places where the bands are found, 

 some change which in them has notably increased their power 

 of reflecting light. As to the nature of this change we can do 

 nothing more than form conjectures, but it seems indubitable 

 that it has had an intimate connection with the formation of the 

 annular mountains, which are found exactly in the central point 

 of these bands. 



8. Physical Rertiarks upon the Eclipses of the Moon and of 

 the Sun, relating principally to the appearances which the former 

 luminary presents during these interesting phenomena. — It has 

 long been observed that the moon does not invariably present 

 the same appearance when totally eclipsed. In by far the 

 greater number of instances this luminary may still be distin- 

 guished ; and in fact it generally exhibits a faint reddish as- 

 pect, more or less distinct, which enables us, with the help of 

 glasses, to recognise the most of its spots. This light was re- 

 markably intense during the eclipse of December 26. 1833, the 

 state of the atmosphere being very favourable for the occurrence. 



MM. Beer and Madler discovered, on that occasion, the 

 smallest objects that are usually detected on the moon's sur- 

 face ; as, for example, the hilly groups which are situated be- 

 tween Pliny and the promontory of Acherusia, each part main- 

 taining its relative degree of illumination as in full moon. The 

 margin of the earth's shadow^ was very distinct, and as a whole 

 it was regularly elliptical. Towards the central part of the sha- 

 dow the objects were less distinctly traced, and the great seas 

 were seen with difficulty, although the spots were visible. In 

 other total eclipses, again, the limits of the shadow and the 

 aspect of the moon itself have appeared much more indistinct, 

 a dark and vapory glimmering being all that could be detect- 

 ed ; and in other cases, as on the 10th of June 1816, the moon 



