496 Changes in the Moon's Surface. [October, 



appearance of Linne, when it is viewed under oblique illu- 

 mination. This conclusion is based upon a comparison of 

 its present appearance with the descriptions of Lohrmann 

 and Madler, and with Herr Schmidt's own observations 

 from 1S41 to 1S43. On this account, it is of importance to 

 notice that the earlier observations by Schroter seem to 

 agree very closely with the appearance which Linne now 

 presents. In Plate IX. of Schroter's "Selenotopographische 

 Fragmente," the place occupied by Linne is marked by 

 a round white spot, and not by the figure of a crater. The 

 spot is distinguished in the plate by the letter v. At page 

 1 Si, Schroter gives the following description of this object: — 

 1 Die sechste Bergader Kommt von einer fast dicht an den 

 siidlichen Granzgebirgen befindlichen, verhaltlich gezeich- 

 neten Einsenkung u, streicht nordlich nach v, woselbst sie 

 wieder eine ohnegefahr gleich grosse, aber ganz flache, als 

 ein weisses, sehr kleines rundes Flecken erscheinende, 

 etwas ungewisse Einsenkung in sich hat.' . . . The obser- 

 vation was made in 17S8, November 5, from 4 hours 30 

 minutes to S hours. The mean time of the observations 

 was 7 days 14 hours after new moon. Schroter employed a 

 power of 161 on his 7 feet reflector. The description of 

 this object as a flat somewhat doubtful crater, which 

 appeared as a round white spot, agrees remarkably with the 

 appearance which Linne now presents under similar condi- 

 tions of illumination. The absence of any mention by 

 Schroter of the small interior crater cannot be regarded as 

 evidence of much weight that this little crater has been 

 subsequently formed. An object so small might easily have 

 been overlooked by Schroter. However, Lohrmann's de- 

 scription, in 1S23,* and that by Madler, in 1S31, do not 

 appear to be in accordance with Schroter's observations, or 

 with the present aspect of the object. My observations 

 were made with a refractor of S inches aperture, and with 

 various powers from 200 diameter to Soo diameters." 



The next communication from which I shall quote is con- 

 tained in a paper in the 5::.. ■;■.:. August, 1S67, and is by 

 Mr. Birt :— 



" The question of change on the moon's surface, supposed 

 to have been manifested in the case of the crater Linne, 

 with which our readers are acquainted, remains undecided. 

 Respighi, on the Continent, as well as several eminent astro- 

 nomers in our own country, having come to the conclusion 



* -A is the second crater upon this plain, — has a diameter which exceeds 

 somewhat one mile, is very deep, and can be seen under every illumination." 

 — Topographic der Mondobtrflache, p. 92 and plate, section IV. 



