Message #168395

[Bathos]

Part 5

Sometimes on a fine night we see a variety of appearances that form
in the sky: 'chasms' for instance and 'trenches' and blood-red colours.
These, too, have the same cause. For we have seen that the upper air
condenses into an inflammable condition and that the combustion sometimes
takes on the appearance of a burning flame, sometimes that of moving
torches and stars. So it is not surprising that this same air when
condensing should assume a variety of colours. For a weak light shining
through a dense air, and the air when it acts as a mirror, will cause
all kinds of colours to appear, but especially crimson and purple.
For these colours generally appear when fire-colour and white are
combined by superposition. Thus on a hot day, or through a smoky,
medium, the stars when they rise and set look crimson. The light will
also create colours by reflection when the mirror is such as to reflect
colour only and not shape.

These appearances do not persist long, because the condensation of
the air is transient.

'Chasms' get their appearance of depth from light breaking out of
a dark blue or black mass of air. When the process of condensation
goes further in such a case we often find 'torches' ejected. When
the 'chasm' contracts it presents the appearance of a 'trench'.

In general, white in contrast with black creates a variety of colours;
like flame, for instance, through a medium of smoke. But by day the
sun obscures them, and, with the exception of crimson, the colours
are not seen at night because they are dark.

These then must be taken to be the causes of 'shooting-stars' and
the phenomena of combustion and also of the other transient appearances
of this kind.