ASTRONOMY AND METEOROLOGY. 349 



zone of 40° to 50°, pale blue, and growing whiter toward the ho- 

 rizon. The darkness of tlie upper sky is generally in proportion 

 to the decrease of moisture. When the air was very clear, there 

 seemed a delicate transparent l)lue veil beneath the balloon, 

 between it and the deeper coloration of the surface of the earth. 



Influence of the Moon on the Condensation of Watery Vapor. — M. 

 Flamraarion states, as a result of his balloon experiments, that 

 often near midnight, when he was below light clouds, he has seen 

 them gradually melt away under the light of the moon, and en- 

 tirely disappear, as takes place on a larger scale by day under the 

 action of the sunlight. Whether this is a mere coincidence, or a 

 direct effect of the moon's influence, he does not undertake to de- 

 termine. — Comptes Bendus, Jidy, 1868. 



Segmentation of Solar Spots. — An interesting fact in solar phys- 

 ics is the segmentation of a large solar spot, described by M. 

 Flammarion, as occurring between May 9, 1868, when it appeared 

 on the east border of the sun, and May 22, when it disappeared in 

 consequence of rotation. — Comptes Rendus, July 13, 1868. 



Eolation Period of the Planet Mars. — According to the new de- 

 termination of Mr. Proctor, the sidereal day of Mars is a period 

 of 24 h. 37 m. 23.73 s., instead of 24 h. 37 m. 27.745 s., as 

 at first obtained. His observations extend over a period of 200 

 years. 



Lunar Crater Linnaeus. — The opinion seems to prevail that there 

 has been no change in the crater ; but that, owing to the peculiar 

 character of the moon's surface in this neighborhood, very slight 

 variations in the illumination serve to produce marked variations 

 in the appearance of the crater. 



Light of the Moon, and Daybreak. — As seen from a balloon by 

 M. Flammarion, the light of the moon (just passed the meridian) 

 and of the dawn of day, at 2 h. 45 m. A. M., U hours before sun- 

 rise, are equal ; after that the light of day increased, while that 

 of the moon relatively diminished. He also recognized that the 

 whiteness of moonlight is only in comparison with our artificial 

 lights ; it becomes reddish in presence of the light of dawn, as 

 gas-light does before moonlight. Even when the light of da\yn 

 is less than that of the moon, it penetrates natural objects, while 

 that of the moon glances over them. Even in the clearest sky, 

 the regions near the earth, as seen from above, are always veiled 

 in vapor. The twinkling of the stars is more feeble in the heights 

 of the atmosphere than at the surface of the earth. 



Lunar Vegetation. — A German astronomer. Prof. Schwabe, has 

 been closely examining certain dark lin<;s which by the aid of the 

 telescope may be seen extending across the slojDes of the highest 

 mountains in the moon. These streaks have been explained vari- 

 ously, some believing them to be the beds of dried-up streams, 

 others, the channels left by torrents of lava. Prof. Schwabe 

 claims to have discovered in these lines a greenish color which ap- 

 pears at certain seasons, lasts a few months, and disappears. He 

 regards them as belts of vegetation. 



Warmth of the Snow Blanket. — Much controversy existed as to 

 the warmth imparted to the earth by a covering of snow, until M. 

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