Idioms and a glimpse of their history

A SHOT OF WHISKEY
In the old west a .45 cartridge for a six-gun cost 12 cents, so did a glass of whiskey. If a cowhand was low on cash he would often give the bartender a cartridge in exchange for a drink. This became known as a "shot" of whiskey.

THE WHOLE NINE YARDS
American fighter planes in WW2 had machine guns that were fed by a belt of cartridges. The average plane held belts that were 27 feet (9 yards) long. If the pilot used up all his ammo he was said to have given it the whole nine yards.

PASSING THE BUCK / THE BUCK STOPS HERE
Most men in the early west carried a jack knife made by the Buck knife company. When playing poker it as common to place one of these Buck knives in front of the dealer so that everyone knew who he was. When it was time for a new dealer the deck of cards and the knife were given to the new dealer. If this person didn't want to deal he would "pass the buck" to the next player. If that player accepted then "the buck stopped there".

COBWEB
The Old English word for "spider" was "cob".

BARGE IN
Heavy freight was moved along the Mississippi in large barges pushed by steamboats. These were hard to control and would sometimes swing into piers or other boats. People would say they "barged in".

HOGWASH
Steamboats carried both people and animals. Since pigs smelled so bad they would be washed before being put on board. The mud and other filth that was washed off was considered useless "hog wash".

CURFEW
The word "curfew" comes from the French phrase "couvre-feu", which means "cover the fire". It was used to describe the time of blowing out all lamps and candles. It was later adopted into Middle English as "curfeu", which later became the modern "curfew".
In the early American colonies homes had no real fireplaces so a fire was built in the center of the room. In order to make sure a fire did not get out of control during the night it was required that, by an agreed upon time, all fires would be covered with a clay pot called-a "curfew".

SLEEP TIGHT
Early beds were made with a wooden frame. Ropes were tied across the frame in a criss-cross pattern. A straw mattress was then put on top of the ropes. Over time the ropes stretched, causing the bed to sag. The owner would then tighten the ropes to get a better night's sleep.