On 17.05.2013 09:53, Dieter Britz wrote:
> How did this originate? Was it some historical
> event, or something people did at one time to
> signal something or other?
>
DROP OF A HAT - "Acting readily or on some single signal. In the 19th
century it was occasionally the practice in the United States to signal
the start of a fight or a race by dropping a hat or sweeping it downward
while holding it in the hand. The quick response to the signal found its
way into the language for any action that begins quickly without much
need for prompting." "Dictionary of Cliches" by James Rogers (Wings
Books, Originally New York: Facts on File Publications, 1985)
Regards, Einde O'Callaghan