What causes dew upon any object?
The air in contact with that object has its vapor condensed, so that the water is deposited on it in the form of dew.
Does the same quantity of dew collect upon all objects?
No; it collects much more upon some objects than upon others.
Upon what objects does it collect the most?
Upon those which radiate or give off heat the best.
Why do objects that are good radiators, collect the most dew?
Because they give off their heat rapidly after sunset, and before morning, become so cold that they condense the vapor in the air touching them, and cause the dew to be deposited on their surfaces.
What objects are the best radiators of heat?
Grass, wood, the leaves of plants, and, in fact, all things of a vegetable nature.