(Agricultural) Wilson Bros., Easton, Pa., similar ad design on two covers showing Grinding Mill & Man with Fowl Scene; first franked with 2¢ red brown on yellow cover with enclosure, other franked with 1¢ gray blue on white cover, both with similar allover ad design on reverse showing Hand Bone Mill, Very Fine. Scott No. 210, 206  Estimate $100 - 150. $0 (Image)