Address of Sir Wm. Thomson at the Glasgow Meeting. 348 
oa to the liquid, and to cause the liquid (homogeneous or 
eterogeneous) and the shell to have sensibly the same preces- 
sional motion as if the whole constituted one rigid body. But 
it is only because of the very long period (26,000 years) of pre- 
cession, in comparison with the period of rotation (one day), 
Would be too small, but that an ellipticity of one or two hundred 
times this amount would not be too small, to compel approx!- 
mate equality of precession throughout liquid and shell. 
_ (2) That with an ellipticity of interior surfave equal to gia) 
if the precessional motive were 26,000 times as great as It 1s, 
the motion of the liquid would be very different from that of a 
(3) That with the actual forces and the supposed interior 
ellipticity of ;1, the lunar nineteen-yearly nutation might be 
affected ‘to about five per cent of its amount by interior 
liquidity. 
(4) Lastly, that the lunar semi-annual nutation must be 
largely, and the lanar fortnightly nutation enormously, affected 
