ON MAPPING THE SURFACE OF THE MOON. 



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By this arrangement objects situated in any area of 5° of longitude and 5° 

 of latitude may be readily designated, and very readily so after a little prac- 

 tice, every space on the moon being thus classified and designated by a Roman 

 Capital with a small Greek character as the index : thus an object situated 

 between 40° and 45° of longitude and 25° and 30° of latitude will be desig- 

 nated by F" 5 , while another situated between 20° and 25° of longitude and 

 20° and 25° of latitude will be designated by A without the Greek index. It 

 is intended to distinguish the separate objects by the Arabic numerals, thus, 

 A* 6. 



It is intended to collect in Tables various information appertaining to each 

 object — as its selenographical coordinates, degree of reflective power, height 

 or depth as the case may be, accompanied by references to more detailed 

 descriptions, previous notices, drawings, and maps, including photographs, 

 each separate Table being headed with one of the symbols in the annexed 

 Table. Thus the Table which is intended to include all objects between 5° 

 and 10° of longitude and 10° and 15° of latitude in Quadrant I. will be headed 

 I. Am ; in Quadrant II., II. Am ; in Quadrant III., III. Am ; and in Quadrant 

 IV., IV. Am. 



When a sufficient number of objects are entered in the above-mentioned 

 Tables, it is intended to arrange them in zones of 5° of latitude, each zone 

 consisting of two parts, west and east, the dividing line being the central 

 meridian, 0° of longitude, mean libration. The zones are arranged as in the 

 preceding Table; in which the numerals indicating zones I. and II., each from 

 0° to 5° of latitude north and south of the equator ; III. and IV., each from 

 5° to 10° of latitude also north and south of the equator, and so on, to zones 

 XXXV. and XXXVL, are placed over the respective latitudes which deter- 

 mine them. By this arrangement zones I., III., V., VII., &c. belong to the 

 north part of the moon's visible hemisphere in Quadrants I. and II., and 

 zones II., IV., VI., VIII., &c, to the south part of the moon's visible hemi- 

 sphere in the Quadrants IV. and III. 



In those instances in which the longitudes of objects exceed 90°, being 

 brought into view by changes of libration, the nomenclature is carried on ; 

 for example, an object having 93° W. longitude and 3° N. latitude is desig- 

 nated by the symbol I. D s . 



In respect to the use of this Form, the Mare Orisium may be adduced as 

 an example of employing the symbols for designating objects. The surface 

 of this Mare is extended upon twelve areas, as follows : — 



and upon these areas various craters and other objects are found. Beer and 

 Madler give ten craters on their large map, and on the small one, published 

 in 1837, Madler gives fifteen additional, but small craters. In the year 

 1863 I ascertained with the Hartwell Equatorial two additional craters to 

 those on the large map, also a small pit-like marking west of Picard. During 

 the year 1865 the existence of several more has been ascertained, so that 

 now at least forty-nine are known, exclusive of fourteen of the fifteen addi- 

 tional craters given by Madler in 1837 *, 



* The fourteen craters here alluded to require identification • ten of them are situated, 

 according to the map, south of I Cf ' and I C*' 3 , near the S.W. border of the Mare CrU 

 sium, one to the west of and in a line with I C^ ' and I C V 3 ' and the rest south of Picard 



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