16 FORMATION OF SHELLS OF ANIMALS, ETC., 
spherules is brought into apposition with another of the 
same kind, as must take place in the supposed conglome- 
rations, the molecules of their adjacent sides will be 
differently attracted from those of the remote ones, and 
the balanced condition of the molecules in both will be 
destroyed. Hence, the molecules which were before con- 
tact at perfect rest, bemg then between equal and oppo- 
site attracting forces, will now be thrown into a state of 
molecular agitation, which must continue until ail the 
molecules of the two spherules have arranged themselves 
around only one centre, and ultimately become blended 
into one perfectly spherical figure, when the mechanical 
conditions necessary for molecular stasis will have become 
restored. The change of form which spherical particles 
undergo as they are in progress of coalescence into spheres 
of larger size being attended with a certain amount of 
motion of their component molecules, renders it certain 
that these molecules im the individual spherules were not 
in a state of absolute contact. Im this respect these 
bodies are like all other hard substances; it being ad- 
mitted, with the complete sanction of fact and experiment, 
that the atoms of all substances, however dense, are at an 
inappreciable distance apart. The fact of this motion is 
shown by the simple inspection of fig. 3, e, which repre- 
sents the sections of two calculi of equal size placed in 
contact, also the section of one which would result from 
their union, whose proper situation and relative size is m- 
tended to be constructed in accordance with the fact of 
the capacities of spheres being as the cubes of their radii. 
The two molecules at the point of contact of these two 
spheres being between equal and opposite attracting forces, 
will be as if not attracted by either sphere, and therefore, 
being in this way removed, each from the attractive iflu- 
