J. R. Mayer on Celestial Dynamics. 401 
_ The combined motions of air and water are to be regarded 
rom the same point of view. If we imagine the influence of 
the sun and that of the interior of our globe not to exist, the 
motion of the air and ocean from east to west is still léft as an 
obstacle to the axial rotation of the earth. 
The motion of the waters of the ocean from east to west was 
long ago verified by observation, and it is certain that the tides 
are the most effectual of the causes to which this great westerly 
are produced in the ocean to those in the atmosphere. This is 
he moon aff 
_* of the globe. Let the earth be divided by the plane of 
‘Meridian in which the moon happens to be, into two hemi- 
abe one to the east, the other to the west of this meridian. 
it is clear that the moon, by its attraction of the eastern hemi- 
Sphere, tends to retard the motion of the earth, and by its at- 
traction of tl tern hemisphere, to accelerate the same rotation. 
_Under certain conditions, these tendencies compensate each 
Am. Jour. nee See Series, Vor. XXXVIII, No. 114.—Nov., 186400 
wo 
