1To Thomas Jefferson from Francis Da Costa, 20 November 1804 (Jefferson Papers)
The interest you have constantly manifested for all discoveries, connected more or less with the prosperity of the United States, will I hope make you forbear the liberty I have taken of Sending you the Sample of a lead mine discovered on my plantation and which I causd. but lately to be opend. The vein has appear’d off the Surface of a Hill almost eighty feet above the highest rise of a creek...