Statue to Sir Isaac Newton. 49 
sixty years and upwards had elapsed, when line proved the 
necessary truth, by rigorous demonstration, the inevitable result 
of undoubted data in point of fact, the eccentricities of the orbits, 
. the directions of the motions, and the movement in one plane of 
a certain position. That wonderful proposition of Newton, which, 
with its corollaries, may be said to give the whole doctrine of 
disturbing forces, has been little more than applied and extended 
by the labors of succeeding geometricians. "eden La Place, 
struck with wonder at one of his comprehensive general state- 
ments on disturbing forces in another proposition, has not hesita- 
ted to assert that it contains the germ of Lagrange’s ce 
quiry exactly a century after the Principia was given to the world. 
The wonderful powers of generalization, combined with the 
boldness of never shrinking from a conclusion that seemed the 
legitimate result of his investigations—how new and even start- 
ling soever it might appear—was strikingly shown in that 
memorable inference which he drew from optical phenomena, 
that the diamond is “an unctuous substance coagulated”; sub- 
sequent discoveries having proved both that such substances are 
carbonaceous, and that the diamond is crystallized carbon; and 
the foundations of mechanical chemistry were laid by him with 
the boldest induction and most felicitous anticipations of what 
as since been effected. The solution of the inverse problem of 
disturbing forces has led Le Verrier and Adams to the discove 
of a new planet, merely by deductions from the manner in pitts 4 
the motions of an old one are affected, and its orbit has been so 
calculated that observers could find it—nay, its disc as measured 
y them varies less than a second from the amount given 
by the theory. Moreover, when Newton gave his estimate of 
the earth’s density, he wrote a century before Maskelyne, who, 
by measuring the force of gravitation in the Scotch mountains, 
gave the proportion to water as 4-716 to 1; and, many years 
after, Cavendish, by experiments with mechanical apparatus, 
(1798) corrected this to 5:48, and Baily, more recently (1842) to 
»°66, Newton having given the proportion as between five and 
six times. In these instances he only showed the way and an- 
ticipated the result of future inquiry by his followers. But the 
oblate figure of the earth affords an example of the same kind, 
with If d the dis- 
Ia nalahypated in- 
this difference, that here he has himself p 
covery and nearly completed the demonstration. From the 
ND NER Se AAI, He TFA OO 
