A set of four original keys from the Titanic sold for ?�20,000 ($26,400) in Christie's much anticipated Out of the Ordinary sale on September 14.
That's an increase of 100% on the lot's ?�10,000 ($13,090) estimate.
Samuel Hemming was the Titanic's lamp trimmer
The keys are connected to a brass fob that reads "TITANIC" on one side and "LAMPS" on the other.
They belonged to Samuel Hemming, who served as the ship's lamp trimmer.
Hemming was one of the crew who gave evidence in the exhaustive inquiry that followed the sinking.
He explained that his role was "to mix the paint, and all that kind of thing for the ship, and to look after all the decks, trim all the lamps, and get them in proper order, and to put the lights in at night-time and take them off at daybreak".
He was asleep when the ship hit the iceberg. The impact woke him but as there was no immediate cause for alarm he went back to bed.
He was woken again by his boatswain, who warned him and his bunkmates: "Turn out you fellows. You haven't half an hour to live.
"That is from Mr. Andrews [the designer of the Titanic, who was aboard], but keep it to yourselves and let no-one know."
Hemming was put in charge of lighting the lamps for the lifeboats and was one of the last off the ship.
He shimmied down a rope into the water and swam (without a lifebelt) to a nearby boat, whose occupants pulled him to safety.
In 2007, the keys that unlocked the binocular case in the Titanic's crow's nest made ?�90,000 ($117,810).
Had the lookouts had access to the case, the iceberg might have been spotted and the disaster prevented.
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