40 FORMATION OF SHELLS OF ANIMALS, ETC., 
portion of material not possessing the property of tenacity. 
Hence such relative proportions of globular carbonate and 
triple phosphate may be conceived to exist together in the 
same calculus as to render the attraction of tenacity acting 
upon its molecules very feeble, or wholly inoperative. In 
which case a compound would result, whose particles in 
themselves are neither attractive nor repulsive; and 
therefore, when brought together into a globular form, 
would owe that form entirely to the attraction of gravita- 
tion. This is an important conclusion, as such a calculus 
would admit of being disintegrated, by reversing the di- 
rection in which gravity, during its formation, acted upon 
its molecules, provided only the attractive force im the re- 
versed direction is greater than that which keeps the mole- 
cules together; and thus it would be the means of adding 
analytical to the synthetical evidence already advanced 
on the subject of molecular coalescence. Now, I may 
observe that such calculi as the above can be prepared, 
and after that disintegrated, on the principle above 
mentioned; but the further consideration of this subject, 
with an account of the experiments required to illustrate 
it, will be given in a separate article on ‘Complete or 
final Molecular Disintegration.’ (See p. 54). And as this 
subject throws no light on crystallization, its introduction 
here would be inconvenient, and therefore I will proceed 
to consider another fact, also showing the feeble condition 
of the force which preserves the molecules of the caleuli 
composed of the globular carbonate and triple phosphate 
in their spherical form, and the near approach that there 
is in these calculi to an extinction of the attraction of 
tenacity. The experiment showing this fact consists in 
exposing a slide prepared according to the formula, and 
having upon it all the varieties of calculi already described, 
