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described by Dr. Klein. Not a trace of such a crater could be 
detected in any of the photographs, though this was no more 
than might be expected, for they do not show such objects near 
the terminator where the crater would be alone visible as such. 
This combined testimony was regarded by selenographers as 
establishing for a certainty the fact that no such crater existed 
in this place prior to 1876. Had then the appearance of anew 
crater been established, and an instance of a real physical 
change decisively made out? Not quite. It had yet to be 
proved for a certainty that such a crater really did exist. 
That there was some object in this region which had not 
been seen before was rendered certain by Dr. Klein’s account ; 
but was it an object which could not have been overlooked ? If 
it were really a great deep crater of the character described by 
Dr. Klein, then it was certain it could not have been overlooked. 
It must be new. But if it turned out to be a mere shallow 
depression, or a mere dark spot, it was not likely to have been 
overlooked, but it might have been, and it would be impossible to 
regard it as being certainly new. If it were merely a hollow, 
or a surface marking, or some small inconspicuous depression,, 
then it might have been overlooked. Which of these was really 
its character? Selenographers awaited with impatience an 
opportunity of settling this point by making additional observa- 
tions. 
April, May, and June came and went, but the weather was so- 
unfavourable that no observations of any importance could be 
made in England. Where the crater ought to be could be 
seen a dark spot such as was described by Dr. Klein. So far 
his observations were confirmed, but the weather had prevented 
this region being seen at sunrise when alone the new object was 
to be seen as a crater. In Germany, however, Dr. Klein was able 
to see the crater again at sunrise, and he described it as a deep 
black crater of considerable size and as conspicuous as Hyginus. 
If therefore these observations of his were confirmed, it must be 
a new formation. 
During the summer and autumn of 1878, the weather con- 
tinued so bad that no suitable observations of the new crater 
could be obtained in England. A discussion arose, however, on 
the question, whether this crater of Dr. Klein’s was really new 
or not. It was pointed out by some astronomers that in the 
lunar photographs, near the place where it was thought that 
Klein’s crater ought to be, there were shown some white and 
some dark spots. 
Some astronomers thought that one of these white spots must 
be the supposed new crater, others thought that one of the dark 
spots was really the crater. After thus identifying the crater 
on a lunar photograph taken prior to 1876, it was argued that 
the crater could not be new, and that it showed that no reliance 
