14 W. A. Norton—Molecular and Cosmical Physics. 
21. Waves of light and of the actinic force originate, like 
those of heat, in the vibratory ne of the atoms, or 
et by the spectroscope, may be chiefly ascribed to diversi- 
n the range and rate of variation of the intensity of the 
Seen acting on the atoms of the electric envelopes of molecules. 
The envelope of the molecule of each substance is in a specia 
condition of equilibrium, both asa whole and in oa its ape ; 
and any sald rea of it, by heat-waves for example, wi 
originate special rates and systems of vibration dacs ose its 
rate as a whole, or in subdivisions 
of greater or less extent, or in its individual atoms. Stationary 
all the conditions ripen cag (8 for the oe of the diverse 
in 
initial waves with the direct and reflex waves from other con- 
tiguous molecular envelopes may also play a certain part in the 
2 RT 
Physicists have sought for a similar theoretical result by con- 
ceiving that the molecules of the vapor or gas are compound ; 
but the fact that each incandescent gas when sufficiently com- 
ressed gives a continuous spectrum, necessitates the supposi- 
tion that the gaseous molecule is composed of an indefinitel 
at number of simple molecules, which cannot be admitted. 
his conclusion cannot be avoided if we allow that to each rate 
of undulation of a ray belongs a particular degree of refrangi- 
ity. 
93, The img 3 of the “Correlation of Forces,” is implied 
in the doctrine of convertible energy that has been briefly set 
forth (p. 12). It applies to the dynamic energies that have re- 
sulted from the operation of cosmical or molecular forces durin, 
certain previous intervals of time. These energies are over an 
above the forces attendant at any instant upon the natural 
statical condition or tendency of things; and hence are so many 
disturbances of the natural equilibrium, and as this always 
tends to assert itself, must continually manifest Poaseives in 
——— with material movements, and these movements 
t be continually undergoing tra nsformations, wherever the 
moni masses ( whether of either of the two ethers or of ordin- 
ary sone come into contact with others at rest. 
24. In the gaseous state of matter the only molecular force in 
ee Tg eae ine 
