THE SUPPOSED NEW CRATEK ON THE MOON. 
139 
attentively studied, and its appearance has been repeatedly 
drawn, and the whole region mapped with especial care. Con- 
sequently it is a portion of the surface of the moon whose 
appearance and configuration are known with much exactitude. 
For many years it has been the opinion of the great majority 
of astronomers that no apparent changes of any magnitude 
were now taking place on the surface of the moon. Nor is it 
difficult to understand how this opinion has become generally 
prevalent. It originated in a summary by the celebrated sele- 
nographer Madler of the differences in the constitution of the 
moon and earth, in which he forcibly pointed out the impos- 
sibility of the view held by the earlier astronomers, which was 
that the moon might be a mere copy of the earth. In these 
remarks Madler indicated that, compared with the earth, with 
its large oceans, abundant vegetation and numerous fauna, the 
moon would be a lifeless desert. In a condensed and far less 
qualified form these remarks were copied into all the text-books 
of astronomy, and constituted the basis of the views commonly 
held by astronomers. 
They gradually came to look upon the moon as an arid life- 
less desert, an extinct volcano. Nor is the real condition of the 
moon, when seen through a telescope, such as to remove these 
views. “Its cold, still, apparently unchangeable surface, so 
utterly unlike what the earth might be supposed to appear as 
seen from the moon, convinces the casual observer that the 
world he then sees is utterly unlike the world he knows. He 
looks for immense cloud masses floating in a dense atmosphere ; 
for wave-tossed seas and winding broad rivers, and there are 
none ; searches for luxuriant forests and green prairies, and they 
are absent. This is enough, and he retires from further con- 
templation of the 4 airless, waterless, lifeless, volcanic desert 5 of 
the text-books.” 
It is, however, a noteworthy fact that this is not the view 
entertained by those who have devoted much time to the study 
of the condition of the lunar surface. These astronomers 
believe that they have found a number of facts which in their 
opinion indicate that great physical changes are slowly taking 
place on the surface of the moon. Schroter, Lohrmann, Grruit- 
huisen, Madler, Schmidt, five most famous selenographers, men 
who have devoted many years to observing the moon, have- 
all pointed out appearances which they had observed, and which 
they believed indicated instances of real change taking place 
on the lunar surface. 
Yet the great body of astronomers still retained their opinion,, 
although they had not devoted any special attention to this 
question ; they contended that no change had been proved to 
have occurred, and refused to alter their opinion that no change 
