Position of the Axis of the Earth’s Crust. 235 
axis of its rotation passes through one of the diameters of the 
wheel, and coincides with what would be the axis of the sphere 
of which the wheel is a section. 
of the poles. If a screw be turned outward so as notably to 
crust could travel freely in any direction, but both impressed 
With the same original rotatory motion, so that without some 
disturbing cause they would continue to revolve forever upon 
the same axis, and as if they were one homogeneous body. Le 
Us assume, moreover, that this crust, though in perfect equilibri- 
um On its center of rotation, was not evenly spherical ex ly, 
