300 J. Lovering—Mathematical and Philosophical 
All our knowledge of mechanical forces is derived from the con- 
scious effort we ourselves make in producing motion. As this 
planets, that the mathematics are neither long-sighted nor short- 
sighted, and that an explanation which suits other forces is good 
enough for gravitation. 
the same direction: he degrades the Newtonian law of attraction 
into an empirical fact, and exalts the laws of Kepler into neces 
sary results of our ideas, . 
Meanwhile, the Newtonian theory of attraction, under the skill- 
ful generalship of the geometers, went forth on its triumphal 
march through space, conquering great and small, far and near, 
until its empire me as universal as its name. The whirlpools 
of Descartes offered but a feeble resistance, and were finally 
