PHILOSOPHICAL 
TRANSACTIONS. 
I. On the Grounds of the Method which Laplace has given in the 
second Chapter of the third Book of his Mecanique Celeste/or 
computing the Attractions of Spheroids of every Description. 
By James Ivory, A. M. Communicated by Henry Brougham, 
Esq. F. R. S. M. P. 
Read July 4, 1811. 
I n every physical inquiry the fundamental conditions should 
be such as are supplied by observation. Were it possible to 
observe this rule in every case, theory would always com- 
prehend in its determinations a true account of the phenomena 
of nature. Applying the maxim we have just mentioned to 
the question concerning the figure of the planets, the mathe- 
matician would have to investigate the figure which a fluid, 
covering a solid body of any given shape, and composed of 
parts that vary in their densities according to a given law, 
would assume by the joint effect of the attraction on every 
particle and a centrifugal force produced by a rotatory motion 
about an axis. The circumstances here enumerated are all 
that observation fully warrants us to adopt as the foundation of 
p - mdcccxii. B 
