1863, 2¢ black, on experimental paper. Lowenberg patent on goldbeaters' skin, vertical pair, full original gum without toning, strong impression, large to huge margins, small margin wrinkle at bottom, Extremely Fine. Scott No. 73E  Estimate $100 - 150. $0 (Image)

1863, 2¢ black, on experimental paper. Lowenberg patent on goldbeaters' skin, block of 4, full undisturbed original gum, encompassed by huge even margins, completely free of any creasing that plagues this delicate paper, an Extremely Fine gem, one of the finest multiples known. Scott No. 73E  Estimate $200 - 300. $0 (Image)

1863, 2¢ black, on experimental paper. Lowenberg patent on goldbeaters' skin, block of 6, full original gum, mostly large margins, exceptional impression, usual creases from natural wrinkling, otherwise Very Fine. Scott No. 73E  Estimate $200 - 300. $0 (Image)

1863, 2¢ black, on experimental paper. Francis patent on greenish wove paper, imperforate, top margin single, o.g., never hinged, large even margins, fresh and Extremely Fine. Scott No. 73E  Estimate $75 - 100. $0 (Image)

1863, 2¢ black, on experimental paper. Francis patent on greenish wove paper, imperforate, bottom margin vertical pair, o.g., hinged at top, never hinged at bottom, ample to large margins, fresh and Very Fine; with 2009 P.F. certificate. Scott No. 73E  Estimate $400 - 600. $0 (Image)

1863, 2¢ black, on experimental paper. Francis patent on greenish wove paper, imperforate, top margin block of 4 with "National Bank Note Company" imprint, o.g., lightly hinged at top, never hinged at bottom, full even margins. bold color, top portion of block with a blue staining, as result of coming in contact with an acidic element (certificate calls this water staining) and the intended effect of this patent paper, otherwise Very Fine; with 2009 P.F. certificate. Scott No. 73E  Estimate $500 - 750. $0 (Image)

1863, 2¢ black, on experimental paper. Francis patent on greenish wove paper, imperforate, block of 4, full o.g., large margins, light diagonal crease at lower right, otherwise fresh and Very Fine; with 1980 P.F. certificate. Scott No. 73E  Estimate $300 - 400. $0 (Image)

1863, 2¢ black, on experimental paper. Francis patent on greenish wove paper, imperforate, bottom margin plate block of 6 with plate number "30" and part imprint, o.g., lightly hinged at top, never hinged at bottom, ample to large margins, deep rich color and exceptional freshness, Very Fine; with 2009 P.F. certificate. Scott No. 73E  Estimate $1,000 - 1,500. $0 (Image)

1863, 2¢ black, on experimental paper. Francis patent on greenish wove paper, imperforate, bottom margin plate block of 12 with plate number "30" and imprint of the "National Bank Note Company", o.g., never hinged, large margin all round, deep color, top stamps with light horizontal crease, otherwise Extremely Fine, a rare experimental paper plate block; with 2009 P.F. certificate. Scott No. 73E  Estimate $2,000 - 3,000. $0 (Image)