294 ANNUAL OF SCIENTIFIC DISCOVERY. 



12th was rainy ; the 13th the atmosphere, being very pure, per- 

 mitted the author to distinguish in the Sea of Serenity a multitude 

 of small disseminated craters. The plain was brilliant, and 

 Linnaeus had the same relative brightness. 



M. Chacornac, who observed the same things at Lyons, arrived 

 at similar conclusions. Father Secchi, of Rome, has already pre- 

 sented to the Academy his own oliservations. It is, then, proved 

 for a certainty that a movement has recently taken place in this 

 region of the lunar world. The magnifying power used was 230 

 to 300 times. 



In the centre of the bright spot which covers the former crater 

 " Linnaeus," there appears a minute black point, indicating a cra- 

 ter of about COO yards diameter. The original crater appears to 

 have been a deep one, and about 10,000 yards in diameter. This 

 small crater was so plainly visible as to have been noticed by Dr. 

 Schmidt, at Athens, by Secchi, at Rome, and by Prof. Lyman, at 

 New Haven, Ct. It was detected at the latter place three days after 

 the sun had risen over the horizon of "Linnaeus," and when the 

 sun was therefore 30 or 35 high upon it. These observations 

 show that any change "which has taken place is not in the nature 

 of a development of a cloud, but imply rather that the old crater 

 has been filled up by an eruption from the small one now visible. 



According to Prof. Respighi, of Rome, the western margin of 

 the small crater in " Linnaeus " is higher than the eastern, and was 

 even visible as a bright point just before the sun rose upon the 

 crater. He' thinks that the historical evidence is not sufficient to 

 prove beyond doubt that a change has taken place. 



Dr. Schmidt states that numerous and careful observations made 

 during the four lunations, both in the waxing and the waning moon, 

 prove that " Linnaeus," under no direction of the sun's light, can 

 now be seen as a normal crater. 



After a careful review of the evidence, Dr. Schmidt concludes 

 that the change which has taken place in this lunar crater cor- 

 responds, on a greatly magnified scale, to the changes produced 

 by mud volcanoes on the earth. He believes that all the internal 

 part of the crater has been filled up by eruptive material, which, 

 by overflowing, has obliterated under gentle slopes the former 

 steep outer walls of the crater. A minute depression, nearly in 

 the middle of the light spot which now marks the place of the cra- 

 ter, has been attributed to the subsequent cooling of the matter 

 within the crater. 



M. Leverrier announced, in June, 1867, that the lunar crater 

 Linnaeus, the disappearance of which had lately caused so much 

 speculation, was in its old place, as had been ascertained by M. 

 Wolff, at the Imperial Observatory. 



Mr. Rutherford has lately examined his photographs of the 

 moon, surpassing in size and minuteness of detail any taken in 

 Europe, with special reference to the supposed lunar volcano, and 

 he states that he cannot detect any change in the brightness of 

 the locality in question. 



