ASTRONOMY AND METEOROLOGY. 293 



disc was less brilliant than that from the lighter part, indicating 

 equality of absorption, and that the color of the darker parts is 

 nearly, if not quite, neutral. 



He" concludes that the ruddy color of Mars is not due to its at- 

 mosphere, but to the materials of the planet's body ; and he re- 

 marks that the polar regions show no color, though the light from 

 them traverses a greater depth.of atmosphere than that from the 

 central parts of the disc. He quotes, as additional evidence, the 

 views of Dr. Zollner respecting peculiarities in the rate at which 

 the brightness of Mars varies with varying phase, and the greater 

 brightness of the disc near the limb. According to Mr. Joynson, 

 there is a permanent dark band extending all around the planet, 

 with only one narrow break in it. Quarterly Journal of Science, 

 July, 1867. 



LUNAR CRATER LINNAEUS. 



There seems to be a difference of opinion among astronomers 

 as to the change which has taken place in the crater in the moon, 

 called Linnaeus or Linne. 



In May, 1867, at a meeting of the French Academy of Sciences, 

 M. Delaunay presented, in the name of M. Camille Flammarion, 

 a note on a change remarked on the surface of the moon in the 

 crater of Linnaeus. It is well known that this crater has recently 

 been subjected to an essential modification. The attention of as- 

 tronomers having been called to this fact by M. Jules Schmidt, of 

 Athens, M. Flammarion chose the moment when the sun rises at 

 the meridian of Linnaeus to study this spot. The sun, being only 

 yet elevated a few degrees above the horizon of the crater in ques- 

 tion, lit it up very obliquely. The slightest irregularities in the 

 conformation of the surface were most distinctly visible. An at- 

 tentive observer would remark at once that Linnaeus is no more a 

 crater; there is no exterior shadow, no shade in the centre. In 

 its place there is only a cloudy white, circular spot, or rather a 

 white stain on the ground. Far from being elevated as a crater, 

 it has a greenish color, like the Sea of Serenity, and seems to be 

 neither in relief nor sunken, but resembles a lake of lighter color 

 than the neighboring plain. 



This crater has therefore descended to the level of the plain, 

 fallen in, or else the plain has been raised to about the level of 

 the crater. The interior appears also filled up, for no shadow is 

 distinguishable, whilst smaller craters, such as A and B of Bessel, 

 A and B of Linnaeus, and those in the neighborhood of Posidonius, 

 show the dark shadow very perceptibly. If Linnaeus had this as- 

 pect at the time when Beer and Maedler laid down their seleno- 

 graphic map, it would have been impossible to have indicated it 

 as a crater. In the map constructed eight years ago by Lecoutu- 

 rier the height is not marked. It appears that it was very deep, 

 10 kilometres in diameter, and that it served as a fixed point for 

 Lorkmann and Maedler. 



On May 11, the sun being more elevated, Linnaeus presented 

 the same aspect as on the evening before. The evening of the 



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