12 W. A. Norton—Molecular and Cosmical Physics. 
(3.) The evolution of heat may also result from the action of 
an electric current,—either compressing the molecular envel- 
luminiferous ether, the energy of which is subsequently ab- 
ulses. 
: 18. All the diverse effective forces in operation, in or upon 
bodies, may act as statical forces, or dynamical forces. In the 
first case the impulses that fall upon the central atoms of the 
primitive molecules are reflected off again, either in electric or 
ethereal waves; and no transformation of motion from ethereal 
The dynamical energy of any moving mass, of either of the 
three varieties of matter, represents the previous expenditure of 
a certain amount of ethereal wave-force, and can disappear only 
in the act of transformation into an equivalent energy of either 
of the other two forms of matter; and each transformation ordi- 
narily soon gives place to another, and so never ending cycles 
of transformation are 
pine through. : 
When the pulses of radiant heat fall upon ordinary molecules — 
one portion of the wave-force is transmitted, another reflected, 
and a third absorbed. ,Absorption is of two kinds, general and 
