France, 1825-35: Russian Platinum Fell 50%

The price of Russian platinum fell dramatically, in about 10 years.  This fact might have been censored in St. Petersburg, but by 1831 Russian ingot was trading around Fr. 16/oz. 

1825: 1 Troy Ounce Platinum (Russian ingot; market) = Fr 30.  (USD $ 5.76)

1831: 1 Troy Oz Platinum (Russian ingot; market) = Fr 16.  (USD $ 2.93)

Citation:  Memorial revue encyclopédique des connaissances humaines (1832) p.216



Prior to 1836:

Citation:  Dictionnaire pittoresque d'histoire naturelle et des phénomènes de la nature ... By Félix-Edouard Guérin-Méneville, Beyer (graveur du 19e s.), Sainson (1837), p.227