BY MOLECULAR COALESCENCE. 19 
particles of matter exposed to its full influence is to bring 
them into the smallest possible space, that is, to arrange 
them in such a solid form as presents 2 maximum of capacity 
with a minimum of superficies (which is the spherical form 
and that only). Gravity acting by itself, and under cir- 
cumstances where it can exert its full force, cannot con- 
sistently with its own laws produce such a figure as the 
one above supposed, and therefore this supposition is 
wholly untenable. The first effect of gravity in the for- 
mation of the minutest spherules was exerted upon the 
atoms or molecules of which they are formed, and no sub- 
sequent operation of this force cam be complete, until 
every such molecule entermg into any one calculus, of 
whatever size it may be, has taken up a definite and 
assigned position. It may be remarked, however, that 
although this observation is strictly true, the form alluded 
to is not geometrically spherical, but after all but a poly- 
gon of a number of sides corresponding to that of the 
molecules or atoms composing its most superficial lamina. 
Having made such observations as apply generally to 
the subject of the coalescence of artificially formed calculi, 
and having shown that this process which, however often 
repeated, affects all the molecules of these bodies, requiring 
in each successive coalescence their readjustment to new 
centres, must be, therefore, strictly molecular; 1 shall 
now consider some particular forms of coalescmg spherules. 
Fig. 2 presents accurate delineations of one or more 
small globules m different stages of molecular coalescence, 
from the dumb-bell figure to the perfect sphere ; (a) shows 
two small spherical particles just brought into contact by 
the mutual attraction of one for the other ; () two others 
which have coalesced sufficiently to acquire the form of a 
dumb-bell; (c) two others whose degree of coalescence is 
