ON MAPPING THE SURFACE OF THE MOON. 299 



It is expected that by the employment of these symbols the distinguishing 

 character of the feature catalogued may be seen at a glance. It is intended 

 that the numboring shoidd proceed consecutively, as objects are added to the 

 separate catalogue in which Eoman Numerals are employed to enumerate 

 the features observed. 



The communication of J. F. Julius Schmidt, Director of the Observatory at 

 Athens, to the 'Astronomische Nachrichten' bears so greatly on the subject 

 of observing the smaller features, that I am induced to give in cvtenso the 

 translation of it, by W. T. Lynn, B.A., F.B.A.S., of the Royal Observatory, 

 Greenwich. 



" Of late years, several observers in England have occupied themselves 

 very perseveringly with the special study of the moon's surface, and have 

 occasionally arrived at conclusions leading to the belief that newly formed 

 mountain ranges are now being discovered upon the moon. Although not 

 in a position myself, after twenty-five years' close observations of the kind, 

 to bring forward even one certain example of new formation, when the 

 question is confined to crater-forms, yet I am far from disputing the fact of 

 the existence of new formations upon the moon. I do not, however, seek 

 them so much amongst the craters, of which thousands of smaller ones, 

 wanting in Lohemann and Madler, are now from time to time being de- 

 tected, but have for about fifteen years past directed my attention especially 

 to the rills, of which I have newly discovered a very great number, and 

 amongst these several of remarkable form, easy to be recognized, which 

 have not been seen since the time of Schroter. With regard to the craters 

 noticed by Messrs. Webb and Birt, in Marius, in Mersenius, near Delisle, b, 

 &c, I have known these since the year 1846, and am in possession of 

 various drawings of them. As importance is being attached to these in- 

 dividual isolated craters (for which there are indeed good grounds), it may 

 be here mentioned that I detected on the 2nd and 4th of January in the 

 present year, in the inner surface of Picard A {Mare Orisium), a small 

 crater, which, together with two others in the northern wall, has escaped 

 all the observers up to this time, although in a region frequently and par- 

 ticularly scanned both by Schroter and myself. 



" As objects repaying careful investigation, I recommend the extremely 

 remarkable rill-systems near Eamsden, and a little westerly of Aristarchus, 

 discovered by me on January 4, 1849, at Bonn, and on May 10, 1862, at 

 Athens. Any one experienced in this department of observation -who will 

 consider, under favourable circumstances, the twelve or thirteen extraordi- 

 nary rills and crater furrows, will perceive for himself how small is the pro- 

 bability that phenomena so remarkable should for so many years have 

 escaped the notice of practised observers, merely on account of external 

 circumstances. 

 " Athens, Jan. 5, 1865." (Signed) " J. F. Julius Schmidt." 



The indefatigable Schroter accumulated a large amount of information 

 relative to the moon's surface, which he published in two quarto volumes, 

 entitled " Selenotopographische Fragmente." It is principally arranged as topo- 

 graphical notices, including, as we have before remarked, numerous measure- 

 ments of mountains, craters, &c, with estimations of brightness, and accom- 

 panied with numerous engravings of the sketches and drawings which he 

 made from time to time. Every conspicuous object, and in many cases very 

 small objects in peculiar situations, have upon the engravings letters refer- 

 ring to _ a description of the objects in the text. These delineations and 

 descriptions are increasing daily in value, and it is easy to see that labours 

 such as those of Schmidt, recorded in the above article, are themselves 



