g Mr. Ivory on the Method of computing 
this inquiry: for, with regard to the earth we know little more 
than that it consists of a solid nucleus, or central part, covered 
with the sea ; and with regard to the other planets, all our 
knowledge is derived from analogy which leads us to think 
that they are bodies resembling the earth. There is one con- 
sideration, however, by which the general research may be 
modified without hurting the strictest rules of philosophizing; 
and that is, the near approach to the spherical figure which 
is observed in all the celestial bodies : and it is fortunate that 
this circumstance contributes much to lessen the great diffi- 
culties that occur in the investigation. But, even with the 
advantage derived from this limitation, the inquiry is extremely 
difficult, and leads to calculations of the most abstruse and 
complicated nature ; and, when viewed in the general manner 
we have mentioned, it far surpassed the power of the mathe- 
matical and mechanical sciences as they were known in the 
days of Sir Isaac Newton, who first considered the physical 
causes of the figure of the planets. That great man was 
therefore forced to take a more confined view of the subject, 
and to admit such suppositions as seemed best adapted to 
simplify the investigation. He supposed in effect that the 
earth and planets at their creation were entirely fluid, and 
that they now preserve the same figures which they assumed 
in their primitive condition ; a hypothesis by which the in- 
quiry was reduced to determine the figure necessary for the 
equilibrium of a fluid mass. The mathematicians, who have 
followed in the same tract of inquiry, have seldom ventured 
to go beyond the limited supposition proposed by Newton. 
They have succeeded in shewing that a mass revolving about 
an axis, and composed of one fluid of a uniform density, or 
