It seems a long way from the ancient hobby of schoolboys but yesterday the largest purchase in stamp collecting history was announced by Stanley Gibbons International, the London stamp dealer that paid more than $10 million for an American collection.

The collection, described by the stamp firm as being probably the finest collection of early U.S. covers in private hands, was put together over 30 years by New York financier Marc Haas, 71.

Stanley Gibbons plans to sell items from the collection separately to philatelists. Jerry Waters, a director of the firm, said that the method of selling had not yet been decided but that it might be by auction.

"It contains some of the absolute gems of U.S. Hilately," Waters said.

There seems no chance that the Haas collection will be kept together as a whole, Waters explained.

"As far as we know there is no one who would be able to buy the collection in its entirety," he said. "Some items may be bought by museums but most, we hope, will go to private collectors."

The collection of 3,000 covers is at present in a bank vault where it is increasing in value at a rate matched only by gold, Waters said.

The period before general issue of stamps in the United States -- pre-1847 -- is represented in the collection by the extremely rare "St. Louis Bears" which were designed by the local postmaster.

Marc Haas also owned the valentine card that has the Annapolis hand stamp on its envelope, and a number of letters bearing the free presidential stamps -- a legitimate early perk of presidents -- of Abraham Lincoln and Thomas Jefferson.

Haas managed to find stamps and covers of extraordinary refinement. He not only got the first general issue 10-cent stamp of 1847 but acquired it in the form of the first cover out of California. He also found two letters, which he bought six years apart, which had been posted as 5-cent letters but stamped with half a 10-cent stamp each, the post office having run out of 5-cent 1847 stamps. The two letters Haas acquired contained the halves of the same 10-cent stamp.

There are stamps from the Civil War, including letters sent through battle lines under flags of truce, plus Pony Express and Wells Fargo covers.

The most expensive individual items of the Haas collection were estimated yesterday to be worth between $100,000 and $200,000 each. The public will not have much of a chance to see, for instance, the wallpaper envelopes that were adapted in the South during the Civil War when paper was scarce behind the blockade, or the "Waterbury Bee" frank, product of an artistic postmaster's idle hours, because, said Waters, they are all worth too much money and "we have to be careful how to show them."