45a 
Relations between Earth and Moon. [August, 
III. SOME INCOMPLETELY UNDERSTOOD AND 
SOME ENTIRELY UNNOTICED 
RELATIONS BETWEEN EARTH AND MOON. 
By 0 . Reichenbach. 
(Ll 
t F the mass of the moon surrounded us as a hollow 
sphere, at its present distance, its aCtion would be dif- 
ferent : for similar reasons the nature and distribution 
of matter within and at the surface of the earth cannot be 
indifferent for the constitution and motions of the moon. 
How could a comet so entirely alter its complexion when 
getting nearer the sun ? How could it go in two, or disperse 
into meteors and mist, or moving from the sun again con- 
dense wholly or in part, if its qualities did not depend on 
position ? If the attraction of planets throws comets into 
new orbits, it must be equally true that the mass and con- 
stitution of the comet accommodates itself to its orbit and 
its adventures. 
What is true of a comet must be true of earth and moon. 
From a long-continuing regular motion we can only infer 
that new components, very gradually transforming former 
results, have produced something like a regular clockwork. 
It is not, for the present, my intention to closely examine 
and discuss why the relations to be enumerated do exist. 
Between the earth and the sun, which has determined the 
configuration of the earth and rules the circulation of the 
oceans, the moon is fitted in agreement with the mutual 
action of sun and earth, and apparently plays the chief part 
in the familiar phenomenon of the tides. 
Long and careful observation has made tidal predictions 
generally correCt ; but if this theory were quite true in its 
premises the height of the flood ought to depend on the 
extent and depth of the local sea, to decrease regularly with 
latitude, and to be next to nothing at and beyond the polar 
circles, — all circumstances, together with various others, not 
in agreement with faCts. 
The tides in the syzigies, when sun and moon aCt in 
common, are larger than in the quadratures, when the lunar 
tides are diminished by the sun. The corresponding lunar 
tides occur in the mean 1*035 days, or 24 hours 40 minutes, 
that is — 
