1875.]  Sclenography : its Past, Present, and Future. 213 
position of the first order, but based his map entirely on the 
result of Madler and Lohrmann. 
In 1865, when the deficiency of Beer and Madler’s map 
in the minuter detail had become more generally recognised, 
the British Association appointed a committee for the purpose 
of making further progress in the mapping and cataloguing 
of the lunar surface, and the result was the production of 
a new system of nomenclature, the commencement of a 
complete lunar catalogue, and the construction of four 
sections of a preliminary outline map ona scale of 200 inches 
to the moon’s diameter. After three years’ work, however, 
the committee was no longer reappointed, and the map and 
catalogue remained in an unfinished condition, making the 
very slowest progress. 
Through both these means, though mainly through the 
labours of Schmidt, much new lunar detail has been 
observed, sketched, and mapped; but little progress has 
been made in a most important branch, namely position 
measures of the lunar formations, though these are abso- 
lutely essential for further progress. Madler’s results were 
insufficient even for the proper delineation of the ‘‘ Mappa 
Selenographica,” and are entirely inadequate for the founda- 
tion of a larger map like Schmidt’s of four times the area, 
much less for one like the proposed final British Association 
map of over seven times as large, or its outline map, which 
has nearly thirty times as great an area; therefore, for the 
proper drawing of these charts; and any smaller than the 
proposed final map of the British Association—namely 
100 inches to the moon’s diameter—would be inadequate; 
more positions of the first order must be made if they are in 
any way to be trustworthy. To supply this want should 
therefore be the first object of further lunar work. 
In October, 1866, Schmidt noticed that the lunar crater, 
Linne, described by Madler, with whom Lohrmann is in 
accordance, as a deep crater 53 miles in diameter, was no 
longer visible, and in November he looked equally in vain, 
and announced, therefore, that Linne had disappeared. 
This attracted at once the attention of astronomers, and 
numerous observations were made; but no trace of the 
crater, as described by Lohrmann, and Beer and Madler, 
could be detected, though soon after a very minute crater 
cone was found to exist on the whitish spot occupying the 
site of Linne. Since then the crater seems to have widened, 
and the remains of a crater of dimensions nearly equal to 
those described by Beer and Madler have been dete¢ted: 
therefore it is generally considered that no real change has 
