It shows the changes about to take place in the weather.
When the quicksilver rises, what kind of weather is indicated?
It indicates fair weather.
When the quicksilver sinks, what kind of weather is indicated?
It indicates cloudy or stormy weather.
Where is the barometer most useful?
It is most useful at sea, to warn the sailors of coming storms.
What use is it to farmers?
They can use it as a guide when planting and gathering their crops, and thus be better prepared for stormy weather.
For what else may the barometer be used?