HAMMOND, MD, Slaves Bill of Sale, 1852 The bill of sale was for a Stanley Boyer (or Bowyer), 16 years of age, and Nancy Cottman, 20 years of age. They were sold by a John N. Denning from Baltimore City to John M. Hammond from Frederick County, Maryland on January 10, 1852 for $575.00. The previous Bill of Sales for these two slaves were recorded in Baltimore County, Maryland. Contributed by: Louis S. Diggs