58 Mare Vaporum and the Lunar Clefts. 



be readily accounted for, partly. by bis having made tbem more 

 bis especial study tban B. and M. could do wbile occupied in 

 a general selenography, and partly by the superior aperture of 

 bis telescope, and, still more, the charming purity of the 

 Athenian sky, far transcending that of Berlin or even Eome. 

 The value of his evidence may be understood from his prin- 

 cipal instance, which relates to the region N.W. of Aristarchus 

 (43). Here, 1862, May 10, with a power of 200 on his 8-in. 

 dialyte (an instrument of inferior quality, from the decompo- 

 sition of the glass), he detected no less than fifteen unknown 

 clefts, some of considerable length and breadth, and not more 

 difficult than many shown by Lohrmann and Madler. He saw 

 also, in the same neighbourhood, a group of new craters of no 

 remarkable minuteness. Schr. had drawn this district six 

 times ; L. and M. must have done so eight or ten times, and 

 under opposite illuminations. Schmidt himself had made 

 twenty-one sketches and numberless observations, without 

 perceiving these objects. On three evenings in 1836, M. drew 

 the very spot, probably with the great 9-i%-in. achromatic at 

 Berlin; and while he inserted some smaller craters, omitted 

 larger ones, as well as the clefts. In May, 1853, Schmidt had 

 missed them all with the same instrument. All circumstances 

 considered, if this is not wholly conclusive, we may look upon 

 it as advancing a considerable way towards a conclusion. 

 Schmidt's figure of this region gives high promise of the 

 hitherto unpublished general Map of six (Paris) feet in dia- 

 meter, which he is preparing solely from his own observations, 

 and which we sincerely trust he may be permitted to complete. 

 His catalogue of clefts gives 11 discovered by Schr., 75 by L., 

 55 by M., 6 by Kinau, and 278 by himself up to Feb. 1865— 

 425 in all • a number which his diligence has probably since 

 considerably increased.* 



Having spent so much time in the general description of 

 these curious objects, we must proceed to the complete and 

 very instructive specimens referred to in the opening of our 

 remarks j of which, and of the principal features of the neigh- 

 bourhood, a diagram accompanies the present paper. It is 

 copied from the Map of B. and M., omitting, however, a great 

 accumulation of detail, and retaining only such features as 

 serve our immediate purpose. The top coincides with the 

 Lunar Equator. Agrijpjpa and Godin will be easily identified 



* One of those ascribed to Schr., the grand cleft in the Alps, was really dis- 

 covered by Bianchini. Gruithuisen detected many, but has in general given very 

 defective identification. Two of his, at least, are I think omitted in this list ; 

 and two if not three more might have been added which I noticed on the floor of 

 Atlas with Mr. Bird's 12-in. silvered glass reflector, 1865, Sept. 7. I have also 

 seen a bent cleft in the interior of JFurnerius with a 5\-iu. object glass. 



