Dark Sun: The Making Of The Hydrogen Bomb

at which we discussed a number of matters, including music and chess.” Among other matters, they may have discussed dissatisfaction within the British Mission at the progress of its work in America, information that Fuchs is more likely to have passed orally than in writing; a cryptic note in J. Edgar Hoover's hand underlined in the file that the FBI opened on Fuchs in 1949 reports such a discussion at about this time and hints that the Soviet New York rezident may have raised the possibility with Moscow Center of having Fuchs arrange to be transferred back to England, which would have been a devastating mistake:

May 8, 1944. F[uchs] advised Russians [that the] work of [the] Brit[ish] Com[mission] on Aftomic] E[nergy] [was] meeting with no success in U.S. & [that there was] dissatisfaction. Russia proposed to send F[uchs] back to G[reat].B[ritain],

Then or later, according to Hoover's notes, Fuchs also advised the Soviets — presumably through Gold, the only contact Fuchs acknowledged in the US — that Britain and the US were slowing down research work on diffusion (they may have been; they were moving on toward industrial development), that the Americans had informed the British that construction of a diffusion plant in England would directly contradict the spirit of the agreement on atomic energy signed together with the Atlantic Charter, and that someone from England was in Washington “at that time looking into details of transferring the work to G[reat] Bfritain].” All this information probably came to Hoover after the war from decoded intercepts. There is no further reference to it in the files that the FBI has declassified; it hints, however, as does much else in Fuchs's testimony, at more extensive communications between Fuchs and Gold than Fuchs chose to acknowledge.

At dinner that April evening, Gold recalled, he and Fuchs also concocted a cover story together, “should either of us ever be questioned,” that they “had met at one of the New York Philharmonic's concerts… in Carnegie Hall; the idea was that we had had adjacent seats and had talked together in the lobby during the intermission.” Gold agreed to look up the date and the program of such a concert so that they would both agree on when they attended and what they heard. After dinner, Gold and Fuchs shared a cab to a bar on Madison Avenue where they had further drinks. Then Gold put Fuchs in a cab to cross Central Park to his apartment on the West Side.

At the meeting they had scheduled the next month in Queens, Fuchs passed Gold “some 25 to 40 pages” of information. Gold could not resist sneaking a look. “After leaving the Elevated I was in the general area where I was to meet John. I still had about five minutes to wait and I recall stopping near a drug store and taking a glimpse of the information… This was in a very small but distinctive writing; it was in ink, and consisted mainly of mathematical derivations. There was also further along in the report a good deal of descriptive detail.” Two minutes of delicious snooping and Gold moved on to his rendezvous with Yatzkov.

In June, the two conspirators met in Brooklyn; Gold remembers Fuchs discussing a personal dilemma of the sort that Fuchs may later have resented Gold revealing:

During this meeting I recall that Klaus Fuchs told me that there was some possibility that his sister who lived in Cambridge, Massachusetts — he did not give me her name, however — might come to New York. He explained to me that his sister was married and had two children, and that she was having great difficulty with her husband and that she was fully intending to leave her husband and come to New York. Should this occur, Klaus told me that he would like very much to be able to share an apartment with his sister… He brought the matter up because he first wanted me to inquire of my superior whether such an action would be all right. I said that I would make the inquiry.

For this meeting, John had given Gold “several typewritten pieces of paper about three by nine inches, of irregular size, which had contained a number of questions relating to atomic energy. The phraseology of these questions was extremely poor, and I had great difficulty in making any sense out of them.” Gold thought the questions had probably suffered in decoding or in translation from Russian. Here may be the origin of Fuchs's conviction that Harry Gold was technically illiterate when in fact he was a competent industrial chemist with a good working knowledge of at least one process of isotope separation. Gold:

I did make what sense I could out of the message, and on this occasion… began to tell Klaus about what further information was desired. I did not get very far along this course because Klaus seemed to take offense at being instructed and said very briefly that he had already covered all of such matters very thoroughly, and would continue to do so.

During July, Fuchs and Gold met yet again, “near an Art Museum” on the West Side according to Gold. Fuchs had important news. “We went for a long walk, almost entirely in Central Park and in the many winding roads and small paths leading through the park itself. This meeting took at least an hour and a half and was a very leisurely one.” Fuchs told Gold he might be transferred, later in 1944 or early in 1945, “somewhere to the Southwest.” Gold was sure later that he had heard Fuchs say Mexico; Fuchs was adamant that he had said New Mexico.

Fuchs revealed during the walk in Central Park, says Gold, “that his brother, Gerhard, was now in Switzerland and was convalescing as a result of having been only recently released from a German concentration camp.” Gold gathered that Gerhard, like Fuchs, was a dedicated Communist. If Fuchs imagined Gold to be his inferior, Gold considered Fuchs fragile and otherworldly and undertook to shelter him. “I also told Klaus that it would be perfectly all right, should his sister come to New York, for him to take an apartment together with her and the children. Actually, I had not mentioned the matter to John at all, but had taken it upon myself to tell Klaus that such a proceeding was O.K.”

Then Klaus Fuchs disappeared. He was scheduled to meet with Gold in Brooklyn at the end of July, in front of the Bell Cinema, close to the Brooklyn Museum of Art. He did not make the meeting. It was standard procedure to schedule backup meetings in anticipation of missed connections. Fuchs also failed to appear at the backup meeting he and Gold had arranged at around 96th Street and Central Park West. Gold's maternal instincts kicked in: “On this second occasion I became very worried, particularly since the area is very close to a section of New York where ‘muggings’ often occur, and also the fact that Klaus was of slight build and might seem an inviting prey.”

Gold met with John. They discussed the problem of Fuchs's disappearance for two hours. “Our principal trouble was to decide whether Klaus, for some reason, was unable to keep the meetings if he was still in New York, or whether he had actually left New York.” Apparently they reached no conclusion. They met again in late August 1944, early on a Sunday morning, near Washington Square. John sent Gold to Fuchs's apartment to ask the physicist's whereabouts. Gold bought a book along the way, Thomas Mann's Joseph the Provider, wrote Fuchs's name and address in it and invented returning it to its “owner” as a pretext for his inquiry. At Fuchs's building, the building superintendent and his wife informed Gold that the physicist had left town. Gold met John again later that morning; they walked along Riverside Drive and “talked at great length.” Stymied, John told Gold to “‘sit tight.’”

At a meeting in early September 1944, another long discussion, Gold finally thought to mention “that Fuchs had a sister who lived in Boston. Now it may be possible that John himself may have brought up the matter of Fuchs’ sister… In any event, John told me that he thought that there lay our best line of inquiry.” By mid-September, John had turned up the name of Mrs. Robert Heineman. She lived, he told Harry, in Cambridge, Massachusetts.

On a Sunday in late September, Gold took the train to Boston and the T subway to Cambridge, found the Heinemans in the phone directory, walked out to their house and knocked on the door. A housekeeper answered; the family, she said, was still away on vacation and was not expected back until October. Gold returned to Philadelphia. When he next met John in New York the Soviet agent was “highly pleased” that they had at least located Fuchs's sister.

Sometime in October 1944, John dictated to Gold a message for Fuchs. Gold printed the message “in engineering lettering” on a card and sealed the card into an envelope. The message consisted of a name — six years later, Gold remembered uncertainly that the first name may have begun with a “J” and that the last name might have been something like “Kaploun” — a Manhattan telephone number and “the information that Klaus was to call the phone number given, any time — on any morning between the hours of 8:00 and 8:30 — and was to give the following message: Merely to say, ‘I have arrived in Cambridge and will be here for… … days.’” (Gold's revelation of a Manhattan phone contact adds another operative to the list of Soviet espionage agents active around