150 



W. D. Lambert — Mechanical Curiosities 



The fluid pressure on any element of surface being 

 normal to the surface, has no moment tending to turn the 

 sphere about its center. Gravity acts as if the sphere 

 were concentrated at its center and does not produce any 



Fig. 7. 



Fig. 7. — Coordinate axes for tlie problem of the floating sphere. 



moment about the center. "We shall suppose that the 

 sphere is submerged to such a depth that the pull of 

 gravity along the s-axis just balances the £;-component of 

 the fluid pressure, so that the forces acting have a zero 

 component along the ^-axis ; we suppose also that the 

 field of force is synnnetrical with respect to the meridian, 

 so that there is no component along the y-axis. "We are 

 interested chiefly in determining whether or not the case 

 of the floating sphere may resemble the case of the rolling 

 one to the extent that there is a small component directed 

 along the x-axis and toward the equator. 



Consider the pressure of an element P of the spherical 



