1947, 5¢ & 10¢ 100th Anniversary U.S. Postage Stamps. Cancelled by "New York N.Y. May 19, 1947" Centenary Exhibition cancel on hand-painted Dorothy Knapp First Day cover, depicting Washington, Jefferson and the various forms of transporting the mails including. horse, stagecoach, train and plane, Very Fine, a rare and desirable Dorothy Knapp cacheted First Day cover. Scott No. 948  Estimate $1,000 - 1,500. $0 (Image)