306 J. Lovering—Mathematicai and Philosophical 
our attention: “The explanation of any action between distant 
bodies by means of a clearly conceivable process, going on in the 
intervening medium, is an achievement of the highest scientific 
value. Of all such actions that of gravitation is the most univer- 
sal and the most mysterious. Whatever theory of the constitu- 
tion of bodies holds out a prospect of the ultimate explanation of 
the process by which gravitation is effected, men of science will 
be found ready to devote the whole remainder of their lives to the 
development of that theory.” : 
e hypotheses of Challis and Le Sage have one thing in com- 
mon; the motion of the ether and the driving storm of atoms 
must come from outside the world of stars. “On either os 
2 
is in the sun, When we qualify the conservation of energy by 
of energy, or of matter itself, would be. 
rom the earliest dawn of intellectual life, a general theory of 
the constitution of matter has been a fruitful subject of debate, 
n i i 
yond the scope of human intelligence as a creation or annihila- 
be 
no t+, Was i 
around the question, whether matter was not infinitely divisible, 
and the atomic philosoph oa 
every new decision on single point there was an appeal, and 
