BY MOLECULAR COALESCENCE. 27 
their number. Now, it may be observed, that although 
this is without doubt true, the reasoning being fully borne 
out by facts, still it does not necessarily follow that there 
should be appreciable interlaminar spaces, but only that 
there should be intervals where the molecules are less 
closely aggregated than in the lamine, the difference 
being only sufficient to affect the transmission of light, 
both ordinary and polarized, and so to produce the ap- 
pearance of laminz in the one case and that of coloured 
rings in the other. This, however, is not to be considered 
as the cause of lamination, but only a circumstance which 
disposes to the production of laminz upon the application 
of the cause. The direct cause of lamination must be 
looked for in some influence which interferes with the 
continuous operation of gravity. Now, imertia is exactly 
such an influence, co-operating at one time with all such 
obstacles as oppose the first communication of motion to 
the coalescing molecules, and at another urging them to 
go beyond the limits assigned by gravity. It is impossi- 
ble that their motions, under such circumstances, can be 
otherwise than irregular and interrupted. And the degree 
of this irregularity depending also upon all other obstacles 
which act upon these molecules in conjunction with in- 
ertia, the number, size, and completeness of the lamin 
in all those calculi must be, to a greater or less extent, 
accidental. These observations are not intended so much 
as an explanation of the process of lamination, as to 
show that the fact of its taking place under such circum- 
stances is more ‘in accordance with than opposed to 
the inference that the formation of these bodies is entirely 
due to the operation of gravity, and that the three stages 
of their formation, namely, the collecting of the spherical 
particles into globular masses, the disintegration of these 
