(1.) The secret mark on this stamp is a small capital G near the pointed left hand end, of the right hand half, of the white line at the bottom of the stamp, below and to the right of the 2 of 1/2.
(2.) There are 40 examples of watermark 186 in the sheet of 200 stamps. Most stamps have a part of the watermark.
(3.) The right third, containing the three legs, is shaded by 31 vertical lines, not counting the dividing line.
(4.) The toe of the upper most foot touches the third line from the center, not counting the dividing line.
(5.) The left third, containing the horse, has 28 similar lines.
(6.) The nose of the horse touches the seventh line from the center, not counting the dividing line.
(7.) The bottom third, containing 3 fleurs-de-lys, has 47 lines, not counting a possible very short line at each end, which is hard to see.
(8.) The upper leaf of each fleurs-de-lys has 2 lines of shading, one line usually being stronger than the other.
(9.) The four triangular shaped blocks, one in each corner of the stamp, have six vertical lines in each 1-mm space, counting both the first and the last.
(10.) The white line surrounding the whole stamp, inside of the colored boundary line, is just 1/2-mm wide all around.
(11.) All the letters of the inscription, except the large G, are exactly the same height, and none of them touch each other anywhere.
(12.) The three dividing lines meet accurately at the center of the stamp, without a blotch.
(13.) There is a colon after the large G:
(14.) The 1/2 is slanted to the right so it almost points to the center of the stamp.
(15.) Exp:do. Ref:Rev. Earee.
(1.) APS cert 207411 "...genuine in all respects."