Letter from the Secretary of the Treasury transmitting a report prepared in obedience to An Act Regulating the Currency of the Foreign Coins in the United States
U.S. Mint Reports (1808)
Mint Director Robert Patterson's report on the assay of foreign coins. The text is also in the American State Papers, finance (class 3), volume 2, no. 275.
Paul Hybert summary: "An assay of foreign coins, from mint director Robert Patterson to Treasury Secretary Albert Gallatin, who relayed it to Congress. Congress’ act of the 10th of April, 1806 fixed the values of certain foreign coins in common use; this report shows that some coins are correctly valued, some coins are slightly over valued, and others are considerably over valued."
A transcription is at: http://www.chicagocoinclub.org/lib/us/asp/cl03.finance/v2/n275.html.