I'm guessing his greater point was that fiat cash in general loses its value.
"On the Continuous Devaluation of the Roman Currency"
http://www.rmki.kfki.hu/~lukacs/ROMLAS.htm
http://www.rmki.kfki.hu/~lukacs/ROMLAS_files/image008.gif
"For in every country of the world, I believe, the avarice and injustice of princes and sovereign states, abusing the confidence of their subjects, have by degrees diminished the real quantity of metal, which had been originally contained in their coins."
https://en.wikisource.org/wiki/The_Wealth_of_Nations/Book_I/...