28 FORMATION OF SHELLS OF ANIMALS, ETC., 
particles, and the final arrangement of their molecules in 
an obscurely laminar form, are all the effects of the opera- 
tion of the same cause—universal attraction or gravity. 
Before concluding the subject of lamination, the coin- 
cidence and blending of the laminze of large calculi, simi- 
larly laminated and of about the same size, requires 
notice. (See Fig. 3, a, 6.) When such calcul as there 
represented coalesce, their laminz will be seen so to coin- 
cide, that, after their union is perfected, the lamine of 
the resultant calculus will have the same relative position 
as those of the components, so that those molecules which 
were in the superficial layers of the latter will also com- 
pose the same layers in the former. But, although any 
given layer of the resultant sphere may contain no other 
molecules than those which had existed in the correspond- 
ing layers of the component spheres, yet such is the 
relation between the capacity and superficial dimensions 
of spheres, that all the molecules of the latter cannot be 
received into the former. As, for instance, the molecules 
at and near to the points of contact of the two spheres 
cannot become circumferential. The mere mspection of 
Fig. 3, diagram e, will show that, as in the progress of the 
supposed coalescence of the two lateral spheres into the 
central one, the molecules occupying the outer parts of 
their surface will, from this position, be the last to reach 
the line indicating the superficies of the aggregate sphere, 
where they must remain; and that, as those on the parts 
of their surface contained within the area of the circle 
intended to represent the section of the same sphere will 
be the first to be carried by the motion of the inner mole- 
cules forwards to the same circle, beyond which, according 
to the hypothesis, they cannot go, and consequently where 
they must remain also, it must follow, that when the 
