thank you for your response. im sorry i dont know what w.t. stood for.i never could find that out. im guessing the w might be for a william and the t his middle name. i know the photagrapher w.t. purviance took photos between the 1860s and the 1880s for stereocards and carte de visites and his office was located in philladeilphia,pa in the early 1860s. ebay has sold many of w.t. purviances stereocards from the 1870s and 1880s. he took pictures of people,soldiers,railroads, trains etc.