216 Fresh Notes on the Grater Linne. 



facts which are already in tlie possession of our readers, and 

 treated the appearances presented by Linne as the first proof 

 furnished with perfect certainty of a change in the moon's 

 surface. Herr Haidinger likewise read a second letter from 

 Schmidt, which we give, as translated by W. J. Lynn, Esq., 

 F.R.A.S., from the Cologne Journal : — 



" An eruption of vapour or ashes is not probable, because a ' 

 shadow of that which covered the crater would be thrown at 

 sunrise and sunset, but this is never the case ; such must also 

 be visible at the phase, which is not the case. Had the crater 

 sunk below, in its place a great shadow would be visible during 

 the phase. Had the ring-mountain been destroyed, the frag- 

 ments would throw shadows, which also is not the case. Had 

 the crater been filled up by an eruption of fluid or powdery 

 matter, without overflowing, the interior black shadow at sun- 

 rise and sunset would indeed disappear, but there would remain 

 a hill, throwing a shadow on the outside. This was the appear- 

 ance seen by Schroter in 1790, in the central crater of Posido- 

 nius, and by Julius Schmidt, in the same object, in the month 

 of February, 1849. But such a mass of matter may also have 

 flowed out over the outside banks, and covered the surrounding 

 declivity, with very gradually sloping inclination. This would 

 prevent the casting of a shadow outside at the phase. Such 

 an event would explain all the phenomena presented by Linne, 

 and it is the kind of event which in the mud volcano of the 

 peninsula of Taman, so closely described by Abich, has so 

 striking an analogue upon our earth. The spreading of the 

 overflowing bright mass over the dark plain gives occasion to 

 the origin of broad formations similar to a halo, which are fre- 

 quently seen upon the moon, especially in the so-called 'Maria.' 

 Here lies the key to new enquiries and points of view ; a hope 

 for the future." 



" Herr Schmidt had already received information from Mr. 

 W. R. Birt, of London, one of his correspondents, that the 

 latter had also confirmed the fact of the disappearance of the 

 crater Linne, and that an account thereof had been communi- 

 cated, by a circular of the Lunar Committee, to astronomers 

 interested in it." 



" Thelong and indefatigable exertions of ourhighly-honoured 

 friend, Julius Schmidt, have therefore been crowned by a result 

 for which even Madler, although he did not resign the hope, 

 remarked, however, that although he had laboured to discover 

 traces of changes on the moon's surface, he was obliged to 

 confess that all the labour hitherto spent upon that object had 

 led to no positive result." (The Natural Sciences, etc., vol. hi. 

 p. 573.) 



" What agonizing interest would this event have given to our 



