60 PHILOSOPHICAL SOCIETY OF WASHINGTON. 
offer this as an explanation of repulsion, and I confess that to me 
repulsion is in its mechanism incomprehensible. *We know the re- 
sult experimentally, and that is resistance to penetration, and reac- 
tion at insensible distances on an undefined boundary which begins 
prior to contact and increases in a high exponential ratio as approx- 
imation progresses. The contact boundary of any solid—even the 
smoothest and hardest—resembles the astronomical limb of Jupiter 
in geometrical indefiniteness. The contact transmitter in the tele- 
phone, the whole range of whose phenomena occurs under pressure 
and so-called contact of varying degrees, illustrates how relative a 
thing is contact. Under high velocities the distinction between 
solids, liquids, and even zriform bodies entirely disappears in re- 
spect to repulsive reaction, though this is the most sensible distine- 
tion between them under low velocities. 
We may, therefore, adopt the conclusion that if any of the ap- 
parently simple properties of the atom are to be thrown out as de- 
rivative and secondary, presumption points to repulsion as the com- 
plex one. We could possibly account for phenomena in a universe 
bound together by purely tensile stress, but most of the sensible 
phenomena of solids—cohesion, affinity, tenacity, etc., including 
nearly all of statics—remain hopelessly unattackable problems un- 
der a hypothesis of pure repulsion, like that of Le Sage, or Pres- 
ton. It is to be noted that the kinetists who freely postulate repul- 
sion and appulsion, without analysis, as a primordial fact, but re- 
luct against compulsion or tension, are forced to the invention of 
the most complicated and gratuitous mechanism and media to ex- 
plain the phenomenon of gravity, and then without attainment of 
result. Le Sage’s atom is too complicated, even without his suppo- 
sitious or extra-mundane operative machinery; and the vortex 
atom is but a mere analytical expression for an unproducible con- 
dition in a figmentary mathematical plenum. 
The thesis that conservation is the characteristic by which we 
identify objective existence will not bear the test of examination 
It is only in the most recent times that such a quality has heen 
known or imagined, and its establishment, both as to matter and 
energy, is justly viewed as the triumph of modern philosophy. The 
evocation of matter from nothing and its relegation to nothing. 
even by the finite will of a wizard, was ever a common and universal 
notion, which did not at all impair the belief in its present reality 
