The 1918 Airmail invert was not the first inverted-center stamp that the government ever unintentionally produced. Three values of the 1869 issue and three values of the 1901 Pan American Exposition issue are known inverted, and most of the previous inverts are scarcer, in some cases far scarcer, than the 1918 Airmail invert. But there is something spectacular about this invert. It has an immediate appeal. And remember, most people in 1918 did not trust airplanes anyway.
Robey immediately announced his discovery, and was inundated with offers to buy the sheet. He wasn’t shy about soliciting them, either. He took a trip from Washington to New York, stopping at stamp dealers along the way, and receiving offers for the sheet. Robey finally sold the sheet for $15,000, a fabulous sum in that day for an error of a stamp still in production. The buyer was Eugene Klein, the famous Philadelphia stamp dealer.
When a stamp is in production, as the 1918 Airmail invert was, there is no way of determining how many of the errors might turn up. As Klein laid out his $15,000 for the sheet of 100, or $150 per stamp, at a time when only a few of the world’s greatest rarities sold for more, he was betting that no more sheets of the error would be found. Klein had more faith in the Bureau of Engraving and Printing quality control than we have today. And Robey? After he got his $15,000 for the sheet for which he paid $24, he became a philatelic celebrity of sorts, speaking at stamp clubs, telling his story over and over again.
No one really knows what Klein had in mind in buying the sheet. He promptly took out an advertisement in a tamp magazine offering the error for sale as singles, indicating a desire to break up the sheet. The price was $250 for a single and $ 175 for a straight-edged single. But the price at which they were offered would have netted him only a small margin of return considering the amount of work involved in making 100 sales. Perhaps Klein wanted the publicity. Or perhaps he wanted to attract the one buyer of stamps who had the resources and inclination to purchase the sheet. Colonel Ned Green was the son of Hetty Green, the famous financier. (Hetty Green was a noted miser: when Ned Green was young, he had a leg infection and Hetty refused to take him to a competent specialist as she did not wish to spend the money. Green lost his leg!) Green was an avid collector of everything from yachts to women. One of his more inexpensive hobbies was stamps. He heard of the sheet, and after the advertisement offering the stamp for sale as singles had appeared, but before the sheet had been broken up, a private sale was arranged. Green bought the sheet for $20,000.
Klein was a reliable, decent sort of man, perhaps the best dealer of his day. He convinced Green to break the sheet, and to slowly offer some of the stamps for sale, a move not naturally in Green’s hoarding disposition. Klein’s reasoning was twofold: he wanted collectors to have the opportunity to own this rarity; and secondly, without any activity in buying and selling fo the stamp, Klein told Green that he risked losing out on his investment as the error would soon fall from public view and desirability. This second argument impressed Green (who was after all Hetty Green’s son) and the sheet was broken up into a variety of blacks and singles. Green numbered each stamp lightly in pencil on the back, corresponding to its position, moving across the top row from left to right, then continuing in the same way down the sheet. Only about 85 of the 100 stamps can now be accounted for. No doubt some of the remaining items are owned by philatelists who view anonymity as the best protection against theft. A block of four was stolen in 1955 while it was on display. But some of the stamps– and we don’t know how many– have been lost. Some say they sunk on one of Green’s yachts; and others report that Green’s collecting room resembled a barn, where perhaps a few were simply thrown away by some over-diligent maid.