from a re-union of particles contained in the air calculated to produce this moist substance. These particles may be also brought from places which are moist or covered with water (for in those places, above all others, it is that dew is abundant). These then re-unite, again resume their aqueous form, and fall down. The same phænomenon takes place in other cases before our own eyes under many analogies.
“Hoar-frost is dew congealed by the influence of the cold air that surrounds it.
“Ice is formed either by the detrition of round atoms contained in the water, and the re-union at scalene and acute angles of the atoms which exist in the water, or by an addition from without of these latter particles, which penetrating into the water, solidify it by driving away an equal amount of round atoms.
“The rainbow may be produced by the reflection of the solar rays on the moist air; or it may arise from a particular property of light and air, in virtue of which these particular appearances of colour are formed, either because the shades which we perceive result directly from this property, or because, on the contrary, it only produces one single shade, which, reflecting itself on the nearest portions of the air, communicates to them the tints which we observe. As to the circular form of the rainbow, that depends either on the fact of the sight perceiving an equal distance in every direction, or the fact of the atoms taking this form when re-uniting in the air; or it may be caused by its detaching from the air which moves towards the moon, certain atoms which, being re-united in the clouds, give rise to this circular appearance.
“The lunar halo arises from the fact of the air, which moves towards the moon from all quarters, uniformly intercepting the rays emitted by this star, in such a way as to form around it a sort of circular cloud which partially veils it. It may also arise from the fact of the moon