afternoon he continued by train to New York. He was rushing to rendezvous with Yatzkov/Yakovlev to pass on the incriminating documents:
I met Yakovlev along Metropolitan Avenue in Brooklyn… where Metropolitan Avenue runs into Queens. It was a very lonely place, particularly at that time of night — It was about 10 o'clock — This meeting had been arranged at Volk's cafe [in May]… [It] lasted about a minute, that was all… We met and Yakovlev wanted to know if I had seen the both of them, “The doctor and the man.” I said that I had. Yakovlev wanted to know had I got information from both of them and I said that I had. Then I gave Yakovlev the two manila envelopes.
Two weeks later, Gold met with Yatzkov/Yakovlev again, “at the end of the Flushing elevated line in Flushing,” to report on his trip to New Mexico.
“The time was in the middle of the evening… Yakovlev told me that the information which I had given him some two weeks previously] had been sent immediately to the Soviet Union. He said that the information which I had received from Greenglass was extremely excellent and very valuable. Then Yakovlev listened while I recounted the details of my two meetings, the one with Fuchs in Santa Fe, the one with Greenglass in Albuquerque.” They talked for two and a half hours.
In Moscow on July 2, an NKVD officer briefed Igor Kurchatov on the progress of the Manhattan Project. The undated notes on that briefing contain details of implosion bomb design that correspond to those Fuchs confessed passing to Harry Gold on June 2. They also contain information on current supplies of fissionable materials that Fuchs was in a position to know. Yatzkov asserted late in life that the source of this summer 1945 briefing information was Perseus and that the information was drawn from material that Lona Cohen had successfully spirited out of Albuquerque, but nothing in the document itself was outside Klaus Fuchs's provenance at Los Alamos. The document justifies reproduction in its entirety; it marks the first transmission to the Soviet Union of details of atomic-bomb design:
TOP SECRET
BOMB TYPE “HE” (HIGH EXPLOSIVE)
The first test explosion of an atomic bomb is anticipated in July of this year.
STOCKS OF ACTIVE MATERIALS.
a) Uranium-235. By April of this year the amount of uranium-235 was 25 kg. Its production now constitutes 7.5 kg per month.
b) Plutonium (element 94). There are 6.5 kg of plutonium on hand at Compound Y [i.e., Los Alamos]. Its production is organized. The plans for production are overfulfilled.
The explosion is anticipated on approximately July 10 this year.
*
The briefing officer's information was accurate so far as it went, but it was less than complete, as Kurchatov would have realized. The officer gave only a general idea of the initiator and made no reference to explosive lenses or to detonators and their placement. But Kurchatov learned vital information, most crucially that there was enough plutonium on hand at Los Alamos to make at least one bomb, that the United States believed it knew how to do so and that enough plutonium was in the pipeline to use up five precious kilograms on a test (the Trinity test device actually used a little more than six).
The Anglo-American Combined Policy Committee met formally and secretly in Washington on Independence Day to carry out a significant provision of the 1943 Quebec Agreement: the British officially gave their approval that day for the use of atomic bombs against Japan, as the agreement provided they must before the United States could act. Donald Maclean was positioned to pass along the information to the Soviets.
Sometime that summer, Yatzkov learned that Abe Brothman was under suspicion of having engaged in espionage. At his regular monthly meeting with Harry Gold in early July, perhaps anticipating problems in maintaining contact if Brothman was questioned and confessed, Yatzkov had Gold prepare a recognition signal “whereby,” says Gold, “some Soviet agent other than himself could get in touch with me.” Like the Rosenberg/Greenglass Jello boxtop, the recognition signal was a piece of ephemera — in this case a memorandum sheet from a laboratory supply house that Gold happened to have in his pocket — on which Gold wrote a street address and which he then divided with his Soviet control. Yatzkov outlined a procedure to follow to make contact using the torn memorandum sheet; Gold would be alerted by two tickets to a New York theatrical or sporting event mailed to him in an otherwise empty envelope.
A test model of the plutonium implosion device on which Klaus Fuchs, David Greenglass and many others at Los Alamos had been working, and on which Igor Kurchatov had been briefed two weeks previously, exploded in its corrugated iron cab on a hundred-foot steel tower at Trinity Site, in the desert north of Alamogordo, New Mexico, at 5:29:45 a.m., July 16, 1945, just before dawn. 1.1. Rabi, the tough-minded Columbia Nobel laureate physicist who visited Los Alamos from time to time as a consultant, was one of many on hand to observe the explosion:
Suddenly, there was an enormous flash of light, the brightest light I have ever seen or that I think anyone has ever seen. It blasted; it pounced; it bored its way right through you. It was a vision which was seen with more than the eye. It was seen to last forever. You would wish it would stop; altogether it lasted about two seconds. Finally it was over, diminishing, and we looked toward the place where the bomb had been; there was an enormous ball of fire which grew and grew and it rolled as it grew; it went up into the air, in yellow flashes and into scarlet and green. It looked menacing. It seemed to come toward one.
A new thing had just been born; a new control; a new understanding of man, which man had acquired over nature.
Fuchs was there to see the new thing he had caused to proliferate, the new control, but no one put a penny in his slot, so he left no record of how the unique experience affected him.
Forewarned with information from his spies, Stalin played dumb at the Potsdam Conference convened outside Berlin when Harry Truman came around the green baize table to inform him of the bomb on the afternoon of July 24. According to Jimmy Byrnes, Truman's new Secretary of State, the President was afraid that if Stalin understood the full power of the new weapon, understood that it might bring a swift end to the Pacific War, the Soviet dictator might expedite his declaration of war against the Japanese and gain a share of spoils he had hardly earned. Truman had confided his expectations to his private diary as soon as he heard of the successful test at Trinity: “Believe Japs will fold up before Russia comes in. I am sure they will when Manhattan appears over their homeland.” So Truman intended to reveal no more of the bomb at Potsdam than was necessary to protect himself from a Soviet charge of perfidy. “I casually mentioned to Stalin that we had a new weapon of unusual destructive force,” the President recalled in his memoirs. “The Russian Premier showed no special interest. All he said was that he was glad to hear it and hoped we would make ‘good use of it against the Japanese.’”
“Stalin… pretended he saw nothing special in what Truman had imparted to him,” Marshal Zhukov reports. “Both Churchill and many other Anglo-American authors subsequently assumed that Stalin had really failed to fathom the significance of what he had heard. In actual fact, on returning to his quarters after this meeting, Stalin, in my presence, told Molotov about his conversation with Truman. ‘They're raising the price,’ said Molotov. Stalin gave a laugh. ‘Let them. We'll have to have a talk with Kurchatov and get him to speed things up.’” Since Kurchatov
