origin of the phrase 'on the wagon'

[kjc0123]

I know the meaning of 'on the wagon' as in 'Don't offer her wine; she's on the wagon.' but not know the reason why the phrase 'on the wagon' hassuch a meaning. Please tell me the origin of the phrase 'on the wagon'?

[VINNY100_2]

ON THE WAGON - "The original version of this expression 'on the water wagon' or 'water cart,' which isn't heard anymore, best explains the phrase. During the late 19th century, water carts drawn by horses wet down dusty roads in the summer. At the height of the Prohibition crusade in the 1890s men who vowed to stop drinking would say that they were thirsty indeed but would rather climb aboard the water cart to get a drink than break their pledges. From this sentiment came the expression 'I'm on the water cart,' I'm trying to stop drinking, which is first recorded in, of all places, Alice Caldwell Rice's 'Mrs. Wiggs of the Caggage Patch' (1901), where the consumptive Mr. Dick says it to old Mrs. Wiggs. The more alliterative 'wagon' soon replaced cart in the expression and it was eventually shortened to 'on the wagon.' 'Fall off the (water) wagon' made its entry into the language almost immediately after its abstinent sister." From the "Encyclopedia of Word and Phrase Origins" by Robert Hendrickson (Facts on File, New York, 1997).

[Postdog]

This originates from public hangings in the UK way back when you had public hangings.

Condemned prisoners would be given a drink prior to hanging (from which came "One for the road" ) and once they had had that drink, they would be put "on the wagon" to be hanged.