Which sentence in this excerpt from Mark Twain's "The £1,000,000 Bank-Note" is an example of satire?

I was admitted by a gorgeous flunkey, and shown into a sumptuous room where a couple of elderly gentlemen were sitting. They sent away the servant, and made me sit down. They had just finished their breakfast, and the sight of the remains of it almost overpowered me. I could hardly keep my wits together in the presence of that food, but as I was not asked to sample it, I had to bear my trouble as best I could.

Now, something had been happening there a little before, which I did not know anything about until a good many days afterwards, but I will tell you about it now. Those two old brothers had been having a pretty hot argument a couple of days before, and had ended by agreeing to decide it by a bet, which is the English way of settling everything.

You will remember that the Bank of England once issued two notes of a million pounds each, to be used for a special purpose connected with some public transaction with a foreign country. For some reason or other only one of these had been used and canceled; the other still lay in the vaults of the Bank.