In the morning the mist is denser above than below, because the sun
draws it upwards; hence tall buildings, even if the summit is at the
same distance as the base have the summit invisible. Therefore,
also, the sky looks darkest [in colour] overhead, and towards the
horizon it is not blue but rather between smoke and dust colour.

The atmosphere, when full of mist, is quite devoid of blueness, and
only appears of the colour of clouds, which shine white when the
weather is fine. And the more you turn to the west the darker it
will be, and the brighter as you look to the east. And the verdure
of the fields is bluish in a thin mist, but grows grey in a dense
one.

The buildings in the west will only show their illuminated side,
where the sun shines, and the mist hides the rest. When the sun
rises and chases away the haze, the hills on the side where it lifts
begin to grow clearer, and look blue, and seem to smoke with the
vanishing mists; and the buildings reveal their lights and shadows;
through the thinner vapour they show only their lights and through
the thicker air nothing at all. This is when the movement of the
mist makes it part horizontally, and then the edges of the mist will
be indistinct against the blue of the sky, and towards the earth it
will look almost like dust blown up. In proportion as the atmosphere
is dense the buildings of a city and the trees in a landscape will
look fewer, because only the tallest and largest will be seen.

Darkness affects every thing with its hue, and the more an object
differs from darkness, the more we see its real and natural colour.
The mountains will look few, because only those will be seen which
are farthest apart; since, at such a distance, the density increases
to such a degree that it causes a brightness by which the darkness
of the hills becomes divided and vanishes indeed towards the top.
There is less [mist] between lower and nearer hills and yet little
is to be distinguished, and least towards the bottom.