Traditional Culture Encyclopedia - Weather inquiry - What is a "barometer"? What's the moral?

What is a "barometer"? What's the moral?

thermometer

Literal meaning

A barometer marked with sunny and rainy weather can predict whether it will be sunny or rainy according to the change of its mercury column or pointer.

meaning

It is often used as a metaphor for signs of changes in the situation.

Xinmin Evening News 1987.3.29: "The printing industry is a sensitive barometer of the publishing industry."

The market bulletin is a barometer of the stock market.