paying attention, listening, questioning the men with whom he worked. “The scientists would come into the shop, and the man who was in charge would assign a man to work with him. Three of us would stand around and talk… and after something was decided upon, the machinist who was given the job would do the job — That way, of course, I did get to learn a lot about what was going on.” He knew something by then about high-explosive lenses, having machined lens molds — forms in which to cast HE — for imploding-cylinder experiments in Walter Koski's group. It was a beginning, something to sustain his hero, something to carry back to New York.
T/5 David Greenglass, Army Serial Number 32882473, left Los Alamos on furlough on December 30, 1944, and arrived in New York on New Year's Day. The Greenglasses had no telephone; Julius Rosenberg turned up at their apartment soon after David got home. “We were trying to enjoy our furlough,” Ruth recalled impatiently, “and… he came to our house for the purpose of discussing [the atomic bomb] with David. We were a little peeved with him because we felt that he was interrupting… ” David remembered a more productive morning[17]:
Rosenberg described to me generally how the atom bomb functions…
He said, Now I will explain and you [will] understand what we are looking for; you tell us what has gone on in the making of the bomb, give us materials, methods of use, experiments necessary… He didn't tell me… who gave him the information. [I asked him.]… He ignored [my question]… He said there was fissionable material at one end of a tube and at the other end of the tube there was a sliding member that was also of fissionable material and when they brought these two together under great pressure… a nuclear reaction would take place. That is the type of bomb that he described.
Rosenberg had described Georgi Flerov's “cannon” design, a uranium gun like the gun that Los Alamos was developing that would be nicknamed Little Boy. Greenglass had not worked on uranium-gun development and knew nothing of gun design; he had been working on HE lens development for the implosion bomb. As of early January 1945, NKVD
Rosenberg asked Greenglass what he was doing at Los Alamos. Greenglass told him he was working on high-explosive lenses. “He told me to write up anything that I knew about the atomic bomb,” David testified, “write it up at night… and he would be back the following morning to pick it up.” Rosenberg also asked for a list of Los Alamos scientists and of possible espionage recruits.
That night Greenglass wrote out his lists and drew “a number of sketches showing various types of lens molds.” The only sketch he reproduced that was subsequently made public was what he called “the flat type lens mold,” which was used at Los Alamos to mold two-dimensional HE assemblies for experiments imploding cylinders. The mold was shaped something like a four-leaf clover. “It has four curves on it,” Greenglass would testify, “… it is hollow at the center and it was used to pour HE into it… The HE took on the shape of the mold and the mold was removed and you had a high-explosive lens.” The two-dimensional HE lens (which had other components besides the molded explosive Greenglass sketched) fit around a length of pipe like an Elizabethan collar with detonators at the apex of each of the four clover leaves; when the detonators were fired, the HE shaped an inward-moving detonation wave that pinched the pipe shut. It was a long way from imploding cylinders to three-dimensional lensed implosion systems, but in fact the two-dimensional experiments proved crucial to the design of the small device at the center of the implosion system — the initiator — that produced a burst of neutrons at the right time to start the chain reaction.
The next morning, Rosenberg came to pick up the lists and sketches that Greenglass had prepared and invited David and Ruth to dinner.
The Rosenbergs rented a modest one-bedroom eleventh-floor apartment, G-ll, at 10 Monroe Street in Knickerbocker Village. When the Greenglasses arrived for dinner, they found another guest on hand, a woman named Ann Sidorovich. The Sidorovichs were friends of the Rosenbergs — Mike, Ann's husband, was an engineer — who lived in the New York suburb of Chappa-qua. Ruth had seen Ann at the Rosenbergs’ apartment several times before, but David had never met her. That evening before dinner, Ruth recalled, “she was there for a while and then she left and we remained. After she had gone, Julius said she was going to come to New Mexico to get the information from David. He said it would be either Ann or someone else, and I asked how [David] would know anyone else if she didn't show up… At that point we were in the kitchen and [Julius] cut this Jello boxtop and he said one-half would be an identification [for] whoever came and he gave me the other half… [Ethel] was standing behind him in the kitchen… She saw it and heard it… I slipped [the boxtop half] into my wallet.”
Ruth kept the boxtop half because she was moving to New Mexico. At about the time of her November visit, Los Alamos had authorized enlisted men to quarter their families nearby. After dinner, David testified, “the Rosenbergs told my wife that she wouldn't have to worry about money because it would be taken care of… She would be able to get out there and live out there, if she wasn't able to work, and money would be forthcoming.”
David and Julius discussed high-explosive lenses. Julius was keen to know more about how they worked and so was his Soviet control. “[Julius] said that he would like [me] to meet somebody who would talk to me more about lenses.” David was willing. Rosenberg briefed David on protocols, Ruth remembered. “I recall him telling [David] that he wanted him not to be obvious or take anything [such as] sketches or blueprints or material but that he should relay whatever he knew from information he had been working on and saw around him.”
That evening, or at some other time during David's January furlough, Julius filled in the Greenglasses on some of his own activities:
Rosenberg told me that the Russians had a very small and a very poor electronics industry, that is, of course, another name for the radar industry, and that it was of the utmost importance that information of an electronics nature be obtained and gotten to him. Things like electronic valves (vacuum tubes) capacitators, transformers, and various other electronic and radio components were some of the things he was interested in. Rosenberg also told me that he gave all of the tube manuals he could get his hands on to Russia, some of which were classified Top Secret.
Elizabeth Bentley notes the curious Soviet penchant for gifts and awards. “For some strange reason,” she writes, “it was a tradition in the NKVD that at Christmas everyone who worked for them — no matter in what capacity — received a gift.” She was another of those who received an Order of the Red Star. Her new control after Jacob Golos's death, Anatoli Gromov (as Gorsky now called himself), who had followed Donald Maclean to America, told her the Order “entitles you to many special privileges;… you could even ride on the street cars free.” The Rosenbergs also received gifts, David Greenglass testified, and Julius had received a citation:
[Julius] stated that he had gotten a watch as a reward… He [showed me the watch.] His wife received also a watch, a woman's watch, and I don't believe it was at the same time… [It was] later, at a later date… I believe they [also] told me they received a console table from the Russians… [Julius] said he received a citation… He said it had certain privileges with it in case he ever went to Russia.
So Julius Rosenberg, like Harry Gold and Elizabeth Bentley, was assured of free trolley rides in Moscow.
A few days later, Greenglass remembered, Julius “asked to see me one night. I had a previous appointment of a social nature to see some personal friends and cut the appointment short in order to meet my brother-in-law.” Greenglass borrowed his father-in-law's car, a 1935 Oldsmobile, and around eleven-thirty at night, “drove to the vicinity of about First Avenue somewhere above East 42nd Street but below East 59th Street,” up the block from a brightly lit saloon. “I parked the car at the curb… Julius Rosenberg walked over to the car and told me to wait. Then he walked away and came back with a man and introduced him to me by a first name which I do not recall. Then the man got into the car and I drove around.”
He drove “all over that area,” Greenglass testified. The man — “a Russian” — “just told me to keep driving and he asked questions about lenses… He wanted to know… the formula of the curve on the lens; he wanted to know the HE used, and means of detonation; and I drove around… and being very busy with my driving, I didn't pay too much attention to what he was saying, but the things he wanted to know, I had no direct knowledge of and I couldn't give a positive answer.” Greenglass nevertheless concluded that the man was technically trained and that,
