> a rough CPI measure of inflation would indicate that the US dollar was worth twice as much in 1900 as at 1800, a total inflation of -50%
Nitpick: you're comparing two currencies that happen to both have been called the dollar.
A dollar in 1800 referred to "371+4⁄16 grain (24.1 g) pure or 416 grain (27.0 g) standard silver" [1]. (To drive home how confusing commodity money is, $2.50, $5 and $10 were defined in gold; cents and half cents in copper.) Because "silver prices rose relative to gold as a reaction to the California Gold Rush" [2], in 1873, the silver dollar was redefined at "371.25 grains" and the gold dollar at "23.22 grains" [3].
None of this, of course, has anything to do with the fiat greenbacks we printed during the Civil War [4] and the ensuing nonsense we had to deal with getting that to play with our metal standards [5], all of which culminated in the Gold Standard Act of 1900 defining a dollar at "25.8 grains of 90% pure gold" [6]. (94% the amount of pure gold per dollar as was in a 1792 Half Eagle per dollar. But again, we're comparing pre- and post-Gold Rush gold. And early industrial versus well industrialised economies.)
Nitpick: you're comparing two currencies that happen to both have been called the dollar.
A dollar in 1800 referred to "371+4⁄16 grain (24.1 g) pure or 416 grain (27.0 g) standard silver" [1]. (To drive home how confusing commodity money is, $2.50, $5 and $10 were defined in gold; cents and half cents in copper.) Because "silver prices rose relative to gold as a reaction to the California Gold Rush" [2], in 1873, the silver dollar was redefined at "371.25 grains" and the gold dollar at "23.22 grains" [3].
None of this, of course, has anything to do with the fiat greenbacks we printed during the Civil War [4] and the ensuing nonsense we had to deal with getting that to play with our metal standards [5], all of which culminated in the Gold Standard Act of 1900 defining a dollar at "25.8 grains of 90% pure gold" [6]. (94% the amount of pure gold per dollar as was in a 1792 Half Eagle per dollar. But again, we're comparing pre- and post-Gold Rush gold. And early industrial versus well industrialised economies.)
[1] https://en.wikipedia.org/wiki/Coinage_Act_of_1792
[2] https://en.wikipedia.org/wiki/Coinage_Act_of_1873
[3] https://en.wikipedia.org/wiki/Dollar_coin_(United_States)#Po...
[4] https://en.wikipedia.org/wiki/Greenback_(1860s_money)
[5] https://www.encyclopedia.com/history/united-states-and-canad...
[6] https://en.wikipedia.org/wiki/Gold_Standard_Act