D4 FORMATION OF SHELLS OF ANIMALS, ETC., 
perfectly crystalline appearance, are deficient in other 
characters belonging to true crystals. They are adherent 
on all sides to the contiguous lines, and therefore they 
have no definite form. These lines, though without doubt 
present in the smaller globules, are not apparent, partly 
from their minuteness, and partly from the great convexity 
of such globules and the high refractive power consequent 
thereon rendering their detection difficult or impossible. 
Hence the cause of these mechanical conditions under 
which the molecules are placed in spherical calculi, which 
render it impossible that their arrangement could be 
otherwise than rectiliear, bemg now shown, and the 
differences between these lines and true crystals poimted 
out, the seeming incongruity before mentioned vanishes, 
and this circumstance itself furnishes a certain amount of 
evidence in proof of the correctness of what has been 
before advanced on both subjects—the formation of 
spheres by molecular attraction, and of crystals by mole- 
cular impulsion. 
It was observed at page 40, that a separate considera- 
tion would be given to a process of complete or final mole- 
cular disintegration, there merely alluded to, and that 
some experiments demonstrative of this process would be 
described. I will therefore now proceed to consider this 
subject, which I may observe is in no respects inferior in 
importance to those already treated of, and perhaps in 
some respects more remarkable. 
ON COMPLETE MOLECULAR DISINTEGRATION. 
In the explanation of the process of coalescence of two 
globules of carbonate of lime into one, it was observed 
that, before these globules could become incorporated, 
