The meaning and origin of the expression: Wet blanket

Wet blanket

What's the origin of the phrase 'Wet blanket'?

A wet blanket is an excellent means of smothering a fire. Being both heavy, flexible and wet it cools the flammable material and moulds itself around it to exclude air. There are many examples in print of this literal usage of 'wet blankets'.

The term began being used in a figurative sense (that is, where no actual blankets or fires were present) in the late 18th century.

A report of the French invasion of Switzerland, in the English newspaper, The Kentish Gazette, December 1798, includes a story where a wet blanket is used to douse a figurative fire:

There was no man so besotted as to not believe that the Swiss would heartily join in the cause, if a general confederacy was formed on the Continent. But if this motion were to be adopted, we should throw a wet blanket on the fire, which was otherwise about to spread through Europe.

In another report of the same conflict, in the same month, The Hampshire Chronicle uses 'wet blanket' in its current 'dampening the spirit' sense:

"Could the fathers, brothers and husbands of the wretched females, victims of lust and cruelty, be dead to all feeling? Can the inhabitants of Stantz forget the destruction of their city? Would they by this vote throw a wet blanket upon their rising spirit?"

'Wet blanket' has moved over time from being a simile (as in when we say someone is like a wet blanket) to a proper metaphor (as in when we say someone is a wet blanket).