A NEW CRATER IN THE MOON. log 



observed this region during the last few years, he felt certaic 

 that no such crater existed there in 1876. He communi- 

 cated his discovery to Dr. Schmidt, who stated, in reply, 

 that in all the numerous drawings he had made of this lunar 

 region no such crater was indicated. It is not shown in the 

 great chart by Beer and Madler, or in Lohrmann's map. 

 Further observation showed that the crater is a deep, conical 

 opening in the moon's surface. Soon after the sun has risen 

 at that part of the moon, and, as later observations con- 

 firm, shortly before sunset there, the opening is entirely in 

 shadow, and appears black. But when the sun is rather 

 higher it appears grey, and with a yet higher sun it can no 

 longer be distinguished. It can, however, be seen when 

 the sun is very high on that part of the moon, appearing 

 then somewhat brighter than the surrounding region, a cir- 

 cumstance which does not hitherto seem to have been 

 noticed by either Klein or Schmidt. 



The moon's surface has been so long and so carefully 

 studied, that it is almost impossible to understand how such 

 a crater as now certainly exists in the Sea of Vapours near 

 Hyginus could have escaped detection. Craters of the kind 

 exist, indeed, in hundreds on the moon's surface. But many 

 astronomers have given years of their life to the study of such 

 objects ; and the centre of the moon's disc, for reasons which 

 astronomers will understand, has been studied with excep- 

 tional care. It seems so unlikely that a deep crater three 

 miles in diameter could escape recognition, that some astron- 

 omers have'not hesitated to regard the newly-detected crater 

 as certainly a new formation. For my own part, though 

 it seems almost impossible to explain how such a crater 

 could have remained so long unnoticed, I can regard 

 the evidence of change as amounting only to extreme pro- 

 bability so far as it depends on the result of past telescopic 

 scrutiny of the moon. 



Admitting that a change had occurred, it would not 

 follow that it had been produced by volcanic forces. 

 It seems far more likely that a floor originally cover- 



