the most extensive element in nature; all other bodies are immersed in
it, and are preserved in their present state of solidity or fluidity by
the attraction of their particles to the matter of heat. Since all known
bodies are contractible into less space by depriving them of some
portion of their heat, and as there is no part of nature totally
deprived of heat, there is reason to believe that the particles of
bodies do not touch, but are held towards each other by their self-
attraction, and recede from each other by their attraction to the mass
of heat which surrounds them; and thus exist in an equilibrium between
these two powers. If more of the matter of heat be applied to them, they
recede further from each other, and become fluid; if still more be
applied, they take an aerial form, and are termed Gasses by the modern
chemists. Thus when water is heated to a certain degree, it would
instantly assume the form of steam, but for the pressure of the
atmosphere, which prevents this change from taking place so easily; the
same is true of quicksilver, diamonds, and of perhaps all other bodies
in Nature; they would first become fluid, and then aeriform by
appropriated degrees of heat. On the contrary, this elastic matter of
heat, termed Calorique in the new nomenclature of the French
Academicians, is liable to become consolidated itself in its
combinations with some bodies, as perhaps in nitre, and probably in
combustible bodies as sulphur and charcoal. See note on l. 232, of this
Canto. Modern philosophers have not yet been able to decide whether
light and heat be different fluids, or modifications of the same fluid,
as they have many properties in common. See note on l. 462 of this
Canto.]

[_When Love Divine_. l. 101. From having observed the gradual evolution
of the young animal or plant from its egg or seed; and afterwards its
successive advances to its more perfect state, or maturity; philosophers