NEWTON. 
fection ; but for want of a proper composi- 
tion of metal, and a good polish, nothing 
succeeded, and the invention lay dormant 
till Hadley made his Newtonian telescope 
in 1723. At the request of Leibnitz, in 
1676, he explained his invention of Infinite 
Series, and took notice how far he had im- 
proved it by his method of Fluxions, which 
however he still concealed, and particularly 
on this occasion, by a transposition of the 
letters that make up the two fundamental 
propositions of it, into an alphabetical 
order ; the letters concerning which are in- 
serted in Collins’s “ Commercium Episto- 
licum,” printed 1712. In the winter, be- 
tween the years 1676, and 1677, he found 
out the grand proposition, that, by a cen- 
tripetal force acting reciprocally as the 
square of the distance, a planet must re- 
volve in an ellipsis, about the centre of 
force placed in its lower focus, and, by a 
radius drawn to that centre, describe areas 
proportional to the times. In 1680 he made 
several astronomical observations upon the 
comet that then appeared ; which, for some 
considerable time, he took not to be one 
and the same, but two diflferent comets ; 
and upon this occasion several letters passed 
between him and Mr. Flamsteed. 
He was still under this mistake, when he 
received a letter from Dr. Hook, explain- 
ing the nature of the line described by a 
falling body, supposed to be moved circu- 
larly by the diurnal motion of the earth, 
and perpendicularly by the power of' gra- 
vity. This letter put him upon enquiring 
anew what was the real figure in which such 
a body moved 5 and that enquiry convinc- 
ing him of another mistake which he had 
before fallen into concerning that figure, 
put him upon resuming his former thoughts 
with regard to the moon; and Picart hav- 
ing not long before, »»?, in 1679, measured 
a degree of the earth with sufficient accu- 
racy, by using his measures, that planet ap- 
peared to be retained in her orbit by the 
sole power of gravity ; and, consequently, 
tliat this power decreases in the duplicate 
ratio of the distance ; as he had formerly 
conjectured. Upou this principle he found 
the line described by a falling body to bean 
ellipsis, having one focus in the centre of 
the earth. And finding by this means, that 
the primary planets really moved in such 
orbits as Kepler had supposed, he had the 
satisfaction to see that this enquiry, which 
he had undertaken at first out of mere curi- 
osity, could be applied to the greatest pur- 
poses. Hereupon he drew up about a 
dozen propositions, relating to the motion 
of the primary planets, round the sun, 
which were communicated to the Royal 
Society in the latter end of 1683. This 
coming to be known to Dr. Halley, that 
gentleman, who had attempted the demon- 
stration in vain, applied, in August, 1684, 
to Newton, who assured him that he had 
absolutely completed the proof. This was 
also registered in the books of the Royal 
Society; at whose earnest solicitation New- 
ton finished the work, which was printed 
under the care of Dr. Halley, and came 
out about Midsummer, 1687, under the title 
of “ Philosophic Naturalis Principia Ma- 
thematica,” containing, in the third book, 
the cometic astronomy, which had been 
lately discovered by him, and now made its 
first appearance in the world : a work which 
may be looked upon as the production of a 
celestial intelligence rather than of a man. 
This work, however, in which the creat 
author has built a new system of natural 
philosophy, upon the most sublime geome- 
try, did not meet at first with all the ap- 
plause it deserved, and was one day to re- 
ceive. Two reasons concurred in produc- 
ing this effect: Des Cartes had then got 
full possession of the world. His philoso- 
phy was indeed the creature of a fine ima- 
gination, gaily dressed out : he had given 
her likewise some of nature’s fine features, 
and painted the rest to a seeming likeness 
of her. On the other hand, Newton had, 
with an unparalleled penetration and force 
of genius, pursued nature up to her most 
secret abode, and was intent to demonstrate 
her residence to others, rather than anxious 
to describe particularly the way by which 
he arrived at it himself: he finished that 
piece in that elegant conciseness, which 
had justly gained the ancients a universal 
esteem. In fact, the consequences flow 
with such rapidity from the principles, that 
the leader is often left to supply a long 
chain of reasoning to connect them, so that 
it required some time before the world 
could understand it. The best mathema- 
ticians were obliged to study it with care, 
before they could make themselves masters 
of it ; and those of a lower rank durst not 
venture upon it, till encouraged by the tes- 
timonies of the more learned. But at last, 
when its value came to be sufficiently 
known, the approbation which had been so 
slowly gained, became universal, and no- 
thing was to be heard from all quarters, but 
one general burst of admiration. “ Does 
Mr. Newton eat, drink, or sleep, like other 
