40 LUNAR AND SOLAR ECLIPSES. SECT. V. 



and moon, divided by their mutual distance, the center 

 of the lunar disc, supposed to be in the axis of the 

 shadow, would receive the rays from the same point of 

 the sun, round all sides of the earth, so that it would be 

 more illuminated than in full moon, if the greater por- 

 tion of the light were not stopped or absorbed by the 

 atmosphere. Instances are recorded where this feeble 

 light has been entirely absorbed, so that the moon has 

 altogether disappeared in her eclipses. 



The sun is eclipsed when the moon intercepts his 

 rays (N. 114). The moon, though incomparably smaller 

 than the sun, is so much nearer the earth, that her 

 apparent diameter differs but little from his, but both 

 are liable to such variations, that they alternately sur- 

 pass one another. Were the eye of a spectator in the 

 same straight line with the centers of the sun and moon, 

 he would see the sun eclipsed. If the apparent diame- 

 ter of the moon surpassed that of the sun, the eclipse 

 would be total. If it were less, the observer would see 

 a ring of light round the disc of the moon, and the 

 eclipse would be annular, as it was on the 17th of May, 

 1836. If the center of the moon should not be in the 

 straight line joining the centers of the sun and the eye 

 of the observer, the moon might only eclipse a part of 

 the sun. The variation, therefore, in the distances of 

 the sun and moon from the center of the earth, and of 

 the moon from her node at the instant of conjunction, 

 occasions great varieties in the solar eclipses. Besides, 

 the height of the moon above the horizon changes her 

 apparent diameter, and may augment or diminish the 

 apparent distances of the centers of the sun and moon, 

 so that an eclipse of the sun may occur to the inhabi- 

 tants of one country, and not to those of another. In 

 this respect the solar eclipses differ from the lunar, 

 which are the same for every part of the earth where 

 the moon is above the horizon. In solar eclipses, the 

 light reflected by the atmosphere diminishes the obscu- 

 rity they produce. Even in total eclipses the higher 

 part of the atmosphere is enlightened by a part of the 

 sun's disc, and reflects its rays to the earth. The whole 

 disc of the new moon is frequently visible from atmos- 

 pheric reflection. 



