BY MOLECULAR COALESCENCE. 45 
molecular coalescence to act continually upon the 
smallest particles of matter. Hence, if the action 
of such a current were a fact, all the nascent mole- 
cules of a crystallizable substance would be simul- 
taneously acted upon by two very dissimilar forces, 
and also in no fixed or definite direction, the direction 
depending upon the position of the attracting particles m 
reference to the direction of the rectilinear current, which 
might at one instant oppose, at another coincide with, 
at other imstants be inclined at varying angles to, the 
direction of this supposed current; and thus these molecules 
would either have their motion only retarded or only 
accelerated, or, if neither of these effects were produced, 
they would be disposed in curves depending upon the 
relative intensities and directions of the motor forces, but 
they would never be disposed in straight lines, as in per- 
fectly rectilinear crystals. A question will now arise as to 
the nature of the agency employed in the communication 
of the impulsive motion to the nascent molecules of the 
erystallizing substance, and its adequacy to account for all 
the phenomena of crystallization. In the preceding course 
of experiments crystallization is shown to take place under 
two sets of conditions, differmg altogether the one set 
from the other. The one is where the formation of 
crystals is the result of chemical action ; the other, where 
crystals are produced on the application of heat to a body 
as yet not at all crystalline, or only very imperfectly so. 
Now, both these are well known to belong to a class of 
cases attended with an evolution of electricity ; so that, in 
the first case, the molecules of carbonate of lime, the 
instant they come into existence, may be inferred to be im 
a state of electrical excitation, and as the composition of 
every molecule is the same, and as the conditions under 
