12 Physical Changes upon the Moon's Surface. [January, 
occurred since 1866, such as, for example, the alteration in 
the size of the small crater within Linne from a diameter of 
barely one-third of a mile in January and February, 1867, 
to a diameter of five times as great in July, 1867. It is 
true the reality of many of these supposed changes is 
doubtful, but alterations in the angle of illumination are 
inadequate to explain them per se. In fa 61 , so far as the 
known observations extend, the alterations undergone by 
Linne in its present condition appear to be perfectly normal, 
and exadfly similar to the changes undergone by all other 
analogously placed and constituted formations. The changes 
are striking, but in no manner strange or unexpected to the 
experienced selenographer. 
The faCts about Linne may be therefore summed up very 
briefly. According to three or more independent selenogra- 
pliers, the most experienced and eminent that Science has 
seen, the objeCt named Linne was a conspicuous crater of 
large diameter and great depth. Now in its place all that 
exists is a traCt of uneven ground, containing a small, 
scarcely visible, insignificant, crater-like objeCt. It is im- 
possible that one could ever be systematically taken for the 
other. It is inconceivable how our three greatest stenogra- 
phers could have systematically and independently made 
the same blunder, and that one blunder only. For in 
no other case do we find any error of this nature. Their 
description must therefore be held to truly describe the 
nature of the formation at their epoch (1820 — 1845). The 
objeCt is no longer of the same size and description. A real 
physical change on the moon’s surface must therefore have 
occurred at this point. This, then, is the conclusion that 
stenographers as a body have arrived at, yet, despite the 
strong evidence on which it rests, it is not generally recog- 
nised by astronomers. 
The next instance of supposed physical change on the 
surface of the moon is one of the most peculiar in the entire 
range of astronomical observations, and is that in the case 
of the crater named Messier by Beer and Madler. In the 
equatorial region of the moon, on the Mare F cecunditatis , 
the westernmost of the great lunar plains, close to one 
another are two small crater plains, according to Beer and 
Madler about 9 miles in diameter. These two formations 
lie isolated on the open plain, and are surrounded by only 
some very low ridges, and mounds, and some rounded de- 
pressions like craters. From the easternmost of the two, 
Messier A, extend two long, slightly diverging streaks, of a 
pale grey colour, which in full moon give the formation 
