Frost.
When the temperature of the air is reduced below thirty-two degrees, what becomes of the moisture collected on plants and other things?
The moisture is frozen.
What is this frozen moisture called?
It is called frost.
What then is frost?
Frost is the frozen moisture on the walls and window panes, and the frozen dew on plants and other objects.
On what objects do we find the most frost?
The most frost is found on objects having the most dew.
What is a heavy dew when frozen called?
It is called a hoar-frost.
When do we have a hoar-frost?
We have heavy frosts when the air is full of moisture.
Why does a heavy frost indicate rain or snow?
Because it shows that the air contains much moisture.
Are heavy frosts usually followed by rain or snow?
Yes; a heavy frost, on two successive mornings, is mostly followed by rain or snow within a few hours.