"W. A. Norton on Molecular Physics. - 215 
electric polarity of the molecule may be induced, which may 
play an important part in the process. 
on the theory of crystallization here offered, the phenom- 
enon of dimorphism, and all changes of form, in the same crystal, 
produced by heat and external causes generally, are but simple 
Tesults of the modifications superinduced by these causes, in the 
‘form, or distance from the central atoms, of the molecular at- 
mospheres; that is, in the physical. features of the molecules, 
“ae which the system of crystallization in every instance de- 
pends, 
Feat. 
The general nature of heat, and the general cause of its evolu- 
64). 
._ Propagation of heat_—Primarily, the heat-pulses are developed 
In the universal ether associated with the atoms of bodies. 
ing universal ether may be in part propagat 
absorbed by the particles they encounter, and partially propa- 
gated onward again in the same manner to mB 
__ The flow of heat from one particle to another of a substance 
tends to disturb the electric condition of the particles; for the 
