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prodigy. In 1667 he was elected Fellow of 
his College; in the fame year he took his Mafter 
of Arts degree, and two years after, on the 
refignation of Dr. Barrow, was chofen Pro- 
feflbr of Mathematics. During the firft 
three years after his elevation to this dig- 
nity, he read leclures on Optics, and on 
communicating his theory of light and co- 
lours to the Royal Society, he was, in 1672, 
elected F.R.S. 
This new theory of Light and Colours, 
though perfectly true, met with confidera- 
ble oppofition, and prevented him from 
publishing his Lectures on Optics. His fub- 
fequent difcovery of that univerfal principle 
in Nature, called gravity, by which he ex- 
plained, in the mofl fatisfaclory manner, 
the vaft fyftem of the univerfe, fhared, for 
a time, the fame fate. Men were unwil- 
ling, at once, to relinquifh the then efta- 
blifhed philofophy of Des Cartes, with 
whofe theory of the univerfe, the world in 
general was fatisfied. 
This French philofopher, Des Cartes, was 
a man of confiderable abilities, an able 
geometrician, and of an inventive genius. 
At the time of his appearance in France, 
the philofophy of Ariftotle was taught in 
all 
