June 03, 1870
To the Senate of the United States:
I transmit to the Senate, for consideration with a view to its ratification, an additional convention to the treaty of the 7th of April, 1862, for the suppression of the African slave trade, which additional convention was signed on this day in the city of Washington by the plenipotentiaries of the high contracting parties.
U. S. GRANT.
Ulysses S. Grant, Special Message Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/203695