10 KANSAS ACADEMY OF SCIENCE. 
TRANSACTIONS. 
A NEW THEORY OF THE SURFACE MARKINGS OF THE MOON. 
By E. Mruuer, Lawrence, Kan. Read before the Academy January 3, 1896. 
Our next-door neighbor, the Moon, although so near, has its mysteries. The 
problems arising from the lunar theories are so many and of such complex nature 
that as yet no complete solution of them has been reached. The dominant fea- 
tures are the craters; and it is practically true that all lunar theories begin with 
them. The mountain ranges, the craters, the cracks and the seams upon the 
Moon, are clearly and distinctly defined with the assistance of a good telescope ; 
and by means of the art of the photographer, there are to-day better maps of the 
lunar surface that is exposed to our view than any maps ever constructed of a 
corresponding portion of the Earth’s surface. 
Three theories have attracted considerable attention, to which a large amount 
of industry, patience and enthusiasm has been given. If not considered presump- 
tuous, I shall add another theory, one that is entirely new and original, so far as 
is known. A brief outline of the first, second and third will be given before 
touching upon the fourth. The first is known as the ‘“‘ volcanic theory,”’ the sec- 
ond as the ‘‘ meteoric,’’ and the third as the “tidal theory.”’ 
All known active and extinct terrestrial craters are volcanic beyond a doubt, 
and the great mass of writers affirm the same to be true of the lunar craters, all 
of which that are exposed to our view being, however, of the extinct variety. No 
craters upon our globe begin to approximate in size the largest of the Moon. 
There are lunar craters 800 miles in diameter, and they range from that size down 
until they become imperceptible. Those large plains upon our lunar surface, 
heretofore called seas, and of oval outline, are now by some classed as craters. 
The largest known crater upon Earth does not exceed 17 miles in diameter. Vol- 
canic action upon our neighbor, the Moon, must have been in its day much more 
terrific than anything of a similar nature upon our own planet. The number of 
lunar craters visible to us is somewhere in the neighborhood of 30,000. Estimat- 
ing one-half the Moon’s surface at about 7,000,000 square miles, and the surface 
of North America, excluding Greenland and the West India islands, at 8,000,000, 
we shall find by the most reliable statistics that North America has only one- 
tenth as many craters, both active and extinct, as one-half the Moon’s total sur- 
face. This apparent discrepancy may be accounted:for when it is considered 
that upon the Earth two powerful agencies— aqueous and atmospheric —have 
been at work for perhaps millions of years, producing a demolition of craters, or 
burying them under successive layers of geologic debris. Without discussing the 
‘*‘voleanic theory’ in detail, this simple reference to it must be considered suffi- 
cient. 
Mr. G. K. Gilbert delivered a very able and interesting address December 10, 
1892, before the Philosophical Society of Washington, on ‘‘The Moon’s Face,”’ 
of which the following may be considered the main thought: Basing his discus- 
sion upon the supposition that when the Moon was in the form of a ring similar 
to the rings of Saturn the time came when the stability of the lunar ring was de- 
stroyed and an indefinite number of moonlets, constituting in fact, a meteoric 
swarm, resulted. Under the superior attraction of one or more of the largest 
