the Attraction of Spheroids. 239 
__ It may be well to apply the general theorem to the simple case in which the first 
solid is a sphere of the radius a’, because both Lacrance and Ivory have used this 
case to show that the reasonings of Lapxace are incorrect. In this instance, then, the 
surface described by the point p” is that of a sphere whose radius is the difference 
between a and a’; and the values of V, 1”, V'", and A, are jra*, 4ra®, 4n(a’—a): 
and 37a’, respectively. 
Substituting these values in the equation 7+ V’—PV’"=2aA, and omitting the 
common factor jr, thg resulting equation 
az +a°—(a@ —a)*=2aa’ 
ought to be identical ;—and so it manifestly is. 
November, 1831. 
