Mr. and Mrs. B. B. Voorhees of Olean announce the engagement of her daughter, Constance Marie Jewell of Rochester, to Seymour H. Knox IV, son of Mr. and Mrs. Seymour H. Knox III of Buffalo. Miss Jewell, daughter of the late John M. Jewell, is a graduate of Olean High School and St. John Fisher College. Her fiance attended the Brooks School and was graduated from Nichols School and Lake Forest College. An August wedding is being planned by the engaged couple.