George Washington letter on sale of slaves up for auction An 1848 runaway slave poster, with a connection to Abraham Lincoln, also is for sale. Check out this story on USATODAY.com: http://usat.ly/2lnazgU A signed letter from George Washington dated Nov. 30, 1774 about the auctioning of 90 slaves and the settling of an estate is among historic documents being auctioned this month by Cohasco, Inc. of Yonkers, Feb. 19, 2017.