Thomas Mercer was born in Harrison county, Ohio, March 11, 1813, the eldest of a large family of children. He remained with his father until he was twenty-one, gaining a common school education and a thorough knowledge of the manufacture of woolen goods. His father was the owner of a well appointed woolen mill. The father, Aaron Mercer, was born in Virginia and was of the same family as General Mercer of revolutionary fame. His mother, Jane Dickerson Mercer, was born in Pennsylvania of an old family of that state. The family moved to Princeton, Ill., in 1834, a period when buffalo were still occasionally found east of the Mississippi river, and savage Indians annoyed and harassed outlying settlements in that region. A remarkable coincidence is a matter of family tradition. Nancy Brigham, who later became Mr. Mercer's wife, and her family, were compelled to flee by night from their home near Dixon at the time of the Black Hawk war, and narrowly escaped massacre. In 1856, about twenty years later, her daughters, the youngest only eight years old, also made a midnight escape in Seattle, two thousand miles away from the scene of their mother's adventure, and they endured the terrors of the attack upon the village a few days later when the shots and shouts of the thousand painted devils rang out in the forest on the hillside from a point near the present gas works to another near where Madison street ends at First Avenue. CROSSING THE PLAINS. In April, 1852, a train of about twenty wagons, drawn by horses, was organized at Princeton to cross the plains to Oregon. In this train were Thomas Mercer, Aaron Mercer, Dexter Horton, Daniel Bagley, William H. Shoudy, and their families. Some of these still live in or near Seattle and others settled in Oregon. Mr. Mercer was chosen captain of the train and discharged the arduous duties of that position fearlessly and successfully. Danger and disease were on both sides of the long, dreary way, and hundreds of new made graves were often counted along the roadside in a day. But this train seemed to bear a charmed existence. Not a member of the original party died on the way, although many were seriously ill. Only one animal was lost.