181 
26. As I give none of these statements on my own individual 
authority, I must refer my hearers to those works in which they 
are treated of, where they will find, if I mistake not, something 
like mathematical demonstration of the truth of the facts. 
Crystallization. 
27. When we leave the consideration of gaseous bodies and 
approach those in a fluid or in a solid state, we have occasion 
to believe that in the molecular constitution exists the reason 
for the difference between these states, and for the phenomena 
of transparency or opacity of bodies. It is not essential to 
my argument to pursue this theme; and it would not be 
possible in the present space of time to do justice to the 
subject: but I must endeavour to present the more complex 
idea of the molecule of mineral structure, especially as the 
mineral state is assimilated in the above passage to the state of 
death, and crystallized matter to the state of life. 
28. I will, in the first place, bring under notice a traced copy 
of the form and arrangement of the molecule of a mineral ( Ido - 
erase), such as is inferred from the chemical analysis and from 
its mode of crystallization. I take this from a work published 
in 1873 by the eminent M. Gaudin, who is Calculator of the 
Bureau des Longitudes and Laureate of the Academie des 
Sciences at Paris. The molecule of this body is believed to repre- 
sent a cube, of which three sides are seen in perspective in the 
accompanying projection. The lines along which the forces 
act are represented by dots, and the nature of the atoms is 
shown by the shading. 
29. In this conception of the molecule, everything is under- 
stood to be arranged with mathematical certainty, and all 
ordered according to fixed and unalterable laws ; so that, how- 
ever numerous the molecules may be, each atom fills the like 
