This is a short answer forum so you will have to do some research into this. The Palace Bar was an actual place in 1912. This was also around the same time as the titanic.
A friend of mine went over this new liner last week - the Titanic - she sails next week - forty-six thousand eight hundred tons - forty-six thousand eight hundred tons - New York in five days - and every luxury - and unsinkable, absolutely unsinkable.
There is a hefty dose of dramatic irony here. Just as the Titanic was a titan that sinks, so is Mr. Birling's logic that is about to sink under the Inspector's interrogation.