One Hundred Interesting Mathematical Calculations: Number 16: How Rich Is Fitzwilliam Darcy?: The mother of the bride-to-be says:
Jane Austen: Pride and Prejudice, Chapter XVII of Volume III (Chap. 59): Good gracious! Lord bless me! only think! dear me! Mr. Darcy! Who would have thought it! And is it really true? Oh! my sweetest Lizzy! how rich and how great you will be! What pin-money, what jewels, what carriages you will have! Jane's is nothing to it -- nothing at all. I am so pleased -- so happy. Such a charming man! -- so handsome! so tall! -- Oh, my dear Lizzy! pray apologise for my having disliked him so much before. I hope he will overlook it. Dear, dear Lizzy. A house in town! Every thing that is charming! Three daughters married! Ten thousand a year! Oh, Lord! What will become of me. I shall go distracted.... My dearest child.... I can think of nothing else! Ten thousand a year, and very likely more! 'Tis as good as a Lord! And a special licence. You must and shall be married by a special licence. But my dearest love, tell me what dish Mr. Darcy is particularly fond of, that I may have it tomorrow.
So how rich is Fitzwilliam Darcy, anyway? What does ten thousand (pounds) a year in the aftermath of the Napoleonic War mean, really?
I have two answers, the first of which is $300,000 a year, and the second of which is $6,000,000 a year.
Consider it first in relative income terms. Output per capita--annual GDP in America today divided by the number of people in America--is valued at some $36,000. Our crude estimates tell us that output per capita in Britain just after the Napoleonic Wars was valued at some 60 pound sterling a year.
Thus in relative income terms--relative to the average of disposable incomes in his society--Fitzwilliam Darcy's 10,000 pounds a year of disposable income gave him about the same multiple of average income in his society as an annual disposable income of $6,000,000 a year would give someone in our society.
On the other hand, my guess is that someone today with a disposable income of $300,000 a year can spend it to get the same or higher utility as Fitzwilliam Darcy could by spending his disposable income of 10,000 pounds a year. This is a guess--a guess that our material standard of living today is some twenty times that of Mr. Darcy's England.
Nevertheless, it is an informed guess. By our standards, early nineteenth century Britain was desperately poor. Moreover, things are made much more complex by the fact that there are lots of things we take for granted--and that are for us trivially cheap--that Fitzwilliam Darcy could not get at any price. Consider that Nathan Meyer Rothschild, richest (non-royal) man in the world in the first half of the nineteenth century, died in his fifties of an infected abscess that the medicine of the day had no way to treat.