i873-j Changes in the Moon's Surface. 499 



" If, then, we compare the actual appearance of Linne 

 with the text of Lohrmann and his successors, it is possible, 

 a la rigueur, to believe that it has undergone a certain change. 

 Linne has always been a deep crater, with elevated margins; 

 its lustre has not changed — its total diameter has remained 

 about the same. A comparison of maps, on the contrary, 

 indicates a real alteration, for these figure a large crater 

 occupying all the space now filled by the white spot. 

 Schmidt thinks that we cannot refuse to attribute great 

 weight to the identity of the indications of these two maps. 

 The authors of the second, having the first at their disposal, 

 it is probable that if they had not found the great crater 

 drawn by Lohrmann, they would have noticed so extra- 

 ordinary a fact. It is not, however, without interest, to 

 compare their indications with that of earlier maps. The 

 picture drawn and presented by Lahire, which is in the 

 library of St. Genevieve, represents Bessel, Sulpicius 

 Gallus, and other little craters, equal to Linne in the map 

 of Madler ; but he does not indicate Linne. He has only 

 many white spots in this part of the sea. Cassini's map 

 appears merely a copy of Lahire with less detail. Accord- 

 ing to Schmidt's note, Schroter seems not to have seen 

 Linne, at least not as one of the principal craters in the 

 Sea of Serenity, although he noticed others that were 

 smaller. 



" If we consult the photographs of the moon, we see, in 

 the large copy of Warren De la Rue (1858), Bessel and 

 Sulpicius Gallus exhibiting an indication of an interior 

 shadow, while Linne figures as a white spot. The same is- 

 seen, though clearer, in the enlarged copy of the magnificent 

 photograph obtained by Mr. Rutherford on the 4th March, 

 1865. 



" The disappearance of the great crater of Linne, then y 

 dates as far back as 1858, if not as far back as Lahire. 

 Apart from the indications supplied by the maps of 

 Lohrmann and Beer and Madler, to which we may oppose 

 the counter indications of Lahire and Schroter, we only 

 possess a single positive document testifying that Linne has- 

 undergone any change, and that is the affirmation of 

 Schmidt that his crater and drawings of 1841 represent the 

 object differently to what is now seen." 



In April, 1869, Mr. Browning described his observations' 

 of Linne, and gave pictures of the shallow crater and the 

 small crater within. These pictures are interesting, as 

 showing the changes which the same object may present, as. 

 seen by the same observer, within a very short space of 



