NEW YORK, DEC. 7 -- Today, on the 49th anniversary of Japan's attack on Pearl Harbor, the navigator's log kept during the mission of the Enola Gay, the B-29 bomber that dropped the first atomic bomb on Hiroshima, failed to sell at auction after questions were raised on its uniqueness.

Christie's made the unusual announcement immediately preceding the lot on the "existence of another apparently authentic version of the Enola Gay log."

Auctioneer Steven C. Massey opened the bidding at $40,000 but no bids emerged. So the log, which bears a "Bomb Away" inscription, passed.

The manuscript offered today was the property of Eileen Lewis, the widow of Capt. Robert A. Lewis, copilot of the bomber. During the long night-shrouded flight to Hiroshima, Lewis made additional entries on the log form and, as if recognizing its historical significance, scribbled "attested as True," above his signature.

Its penciled entries on yellow ledger, never before published or exhibited, carried a pre-sale estimate of $100,000 to $150,000.

The existence of another log became known shortly before the sale. It is in the hands of Enola Gay navigator Theodore "Dutch" van Kirk. He asserts there could be only one original and that he has it.

"We got spooked on this one," said Mary Ellen Sinko, assistant curator of the Forbes Magazine collection. "I got my instructions not to bid on it." At Christie's in 1979, Malcolm S. Forbes paid $85,000 for Capt. Lewis's handwritten, on-board diary of the "Little Boy Mission #1."

Also in the audience was David Kirschenbaum of the Carnegie Bookshop. Kirschenbaum said he had purchased the original Enola Gay diary written by Capt. Lewis at a Parke Bernet Gallery for $17,000 years before Forbes purchased the diary at Christie's. "Captain Lewis came down to the shop often -- you know, he lived in New Jersey -- and told me a lot of things about the war.

"I know of two or three dealers who were interested in the log, but we were all scared off by the sales notice," said Seth Kaller, president of Sunset Historical Gallery of Asbury Park, N.J., moments after the auction. "I learned about the statement in an abbreviated form about three days ago," said Kaller. "Based on that we couldn't have given a bid. Now Christie's and the owner will have the time to carefully study their document and compare it with the other and perhaps they'll rewrite their description. If it turns out to be a copy, it will still have considerable value." Kaller declines to estimate how much it might bring.

Christie's also revealed today that the numerical portion of the log offered for sale -- the scores of neat numbers indicating flight conditions such as altitude, air speed, temperature and wind speed -- "is in an unidentified hand. Therefore, Christie's cannot determine authoritatively that this log was maintained during the mission."

"In theory, there should only be one log," Chris Coover, Christie's manuscript expert, commented today. "It is a mystery," he said.

Reached after the auction, Coover said: "I was very disappointed, largely for the sake of the owner. At this point, she has no intention of doing anything further with the log. We still have absolute confidence that the log we offered was carried into the plane."

Speaking from his home in Novato, Calif., just hours before the auction, van Kirk said: "I'm very confident that the log I have in my possession was the one I maintained during the flight. The only reason I contacted Christie's was I wanted to maintain the integrity of my log."

Van Kirk said he could think of "several scenarios" in which a copy of his navigator's log could have been made, "but I don't want to go into them." He also said that except for a short time, just before Japan's surrender at the end of World War II, the log has been continuously in his possession.

The 69-year-old retired chemical engineer indicated he was still keen on donating his log to the National Air and Space Museum but said the gift was contingent on the completion of the Enola Gay restoration and the display of his log. "I don't want that document locked away in some locker."

Asked if he was aware of a log in Capt. Lewis's possession, van Kirk said, "I knew he had a copy of it."

Roosevelt initiated the top-secret Manhattan Project shortly after Albert Einstein's urgent 1939 letter to him on the military use of nuclear weapons. (Forbes purchased that letter in 1986 at Christie's for $220,000.)

Two billion dollars and 3 1/2 years later, the four-ton bomb, code-named Little Boy, was ready. At 8:15:17 a.m. on Aug. 6, navigator van Kirk made his last entry in the left-hand column of the second log sheet. It was precise and to the point: "Bomb Away."

Another memento from the flight consigned by Capt. Lewis's widow, a single pair of standard-issue black metal binoculars, with their original black leather straps and fleece-lined carrying case, sold today for $13,200 (against a pre-sale estimate of $7,000-9,000). On the inside of the leather lid, Lewis wrote: "Aug. 6 1945/Hiroshima/Capt. Robert A. Lewis" and also on the back of the case's catch flap, "Capt. R.A. Lewis."

Other than the flop of the flight log, Christie's daylong sale of printed books and manuscripts performed solidly, bringing in $1.7 million, slightly above the pre-sale high estimate.

Among the more unusual items that did sell was Abraham Lincoln's "pen of liberty," reportedly used by the president to sign the Act of Emancipation of the District of Columbia slaves on April 16, 1862. It was bought by Hampton University in Virginia for $77,000, dramatically above its high estimate of $7,000.