io Physical Changes upon the Moon's Surface. [January, 
For the reasons detailed in the above, therefore, seleno- 
graphers consider that the attempt to show that Linne has 
not changed has entirely failed, but that in the case of this 
crater we have an instance of real physical change on the 
moon. With regard to the nature of this change little 
definite has as yet been ascertained, and it will require a 
long examination of this region with powerful telescopes to 
determine what change really has occurred. From nume- 
rous observations the explanation agreeing best with the 
present conditions of the surface is that the walls of the 
old crater have collapsed and fallen into the interior. By 
this means the interior would be nearly completely filled up, 
leaving, however, a sort of rough, cone-like, small crater 
towards the centre. Under exceptionally favourable atmo- 
spheric conditions, with the assistance of a powerful tele- 
scope,* the surface immediately around the small crater has 
been seen to present the appearance of being rough and 
irregular. Round what would have been the border of the 
old crater are numerous mounds and rough blocks, and on 
the east is one if not two low hills or peaks, presenting the 
appearance of being portions of the old wall. The diffi- 
culty of making these observations is very great, and they 
are only possible in the very finest atmospheric conditions. 
A prolonged examination of this region, however, would 
amply repay the labour. 
There is one other point on which a remark must be 
made, and that is with reference to an apparently generally 
spread misconception of the change which Linne is supposed 
to have undergone. Thus, in the interesting article on this 
subjedt in the “ Quarterly Journal of Science ” for October, 
1873, Mr. R. A. Prodtor says : — “ Mr. Browning, after con- 
sidering the evidence afforded by his own observations, 
considered in connedtion with those made by others, arrives 
at the conclusion that ‘ there is scarcely any ground for 
supposing that any change has occurred in this small but 
celebrated crater.’ ” Mr. Prodtor then adds — “ These re- 
marks appear to me to contain the gist of the whole matter. 
We see that Linne has a surface so constituted that as the 
sun is rising there, and so pouring his rays very obliquely, 
there is a continual change of aspedt precisely resembling 
that which can be recognised when certain kinds of rock 
surfaces, and especially crystalline formations, are viewed 
under oblique illumination. We know that in such cases 
the tints vary, not only absolutely but relatively, insomuch 
* With an aperture of g| inches, and a power of 600. 
