66 W. A. Norton on Molecular Physics. 
ser the physicists of the present day there seems to be a 
wing inclination to discard the notion of an electric fluid as 
Sintancs from the ether of pak and attempts have been made 
by Challis, Tyndall, and others, to frame a consistent dynamical 
theory of molecular forces and "phenomena, based upon the sup- 
posed existence of only two forms of matter, viz: gross matter, 
and the ether of space. The fundamental’ position taken b 
these distinguished physicists is that the molecular forces, in- 
cluding heat, are conveyed by purely oscillatory waves, ‘and 
originate in a vibratory motion of the ultimate particles of bod- 
ies. Against this idea, however plausible it may seem, and 
however admirable may be the ingenuity and skill with which 
it has been sustained, many serious objections may be urged. 
One or two of these may be briefly sta 
1. No possible mode of explaining the phenomena of elec- 
tricity and magnetism has yet been indicated by the advocates 
of this theory. The electric fluid is expelled by them from the 
vast field it has sear occupied, but all attempts to supply its 
place have proved futil 
2. Another obvious ae is that vibratory motions of gross 
atoms are supposed to originate the forces by which such atoms 
are primarily aggregated into masses, whereas it is essential to 
the possibility of such vibrations that contiguous atoms should 
exercise a mutual action upon one another, that is, be previously 
cs sie al We must suppose, then, the existence originally of 
er forces, to bring isolated atoms together and make the sup- 
eee forces due to vibratory motions of the atoms , possible; 
that is, these latter forces become possible only when there is no 
longer any farther occasion for them. We have seen that an- 
other possible origin may be ascribed to such oscillatory waves 
that does not involve the physical i aggre ~ referred to, 
from which those who seek for the key to all molecular phenom- 
ena in the motions of gross atoms, can bunaly escape. 
8. The notion advocated by Ty ndall in his admirable work 
on ‘ Heat considered as a mode of Motion,” that heat and light 
nate in a vibratory motion of ordinary atoms, involves the 
supposition that these atoms are capable of vibrating at the 
Jes emit sound; and that t since a musi pair gtr vibrates more 
tox aoe re as it is. eee * — cae rp may vi- 
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