We were fairly sure by now that we would be able to test the Fat Man, the implosion-type bomb, sometime around the middle of July. (At no time was there any idea of testing the gun-type bomb.) Planning for this operation, which carried the code name of Trinity, had begun back in the spring of 1944 when Oppenheimer and I decided that a test might be necessary to make certain that the complex theories behind the implosion bomb were correct, and that it was soundly designed, engineered, manufactured and assembled—in short, that it would work.
We thought then that we might want to explode the first bomb inside a container, so that if a nuclear explosion did not take place or if it was a very small one, we might be able to recover all or much of the precious plutonium. Also, we wanted to prevent its being scattered over a wide area and creating a health hazard that would make it necessary to guard the area against trespassers for many years.
Consequently we ordered from Babcock and Wilcox a heavy steel container, which because of its great size, weight and strength was promptly christened Jumbo.1 To move it from the manufacturing plant in the East to New Mexico, it had to be loaded onto specially reinforced cars and carefully routed over the railroads. At the nearest railroad stop to the test site it was unloaded onto a specially built trailer with some thirty-six large wheels, and then driven overland about thirty miles to Alamogordo.
But by the time of the test we had decided we would not need to use Jumbo, for we had learned enough to be reasonably certain of a fair-sized nuclear explosion. Even if it were as low as 250 tons, as many of our scientists were predicting, the container would only create additional dangers.
It is interesting to speculate about what would have happened, with the actual explosion of almost twenty thousand tons, if we had used Jumbo. That the heat would have completely evaporated the entire steel casing is doubtful. If it did not, pieces of jagged steel would probably have been hurled for great distances.
The scientist in charge of the test was Dr. K. T. Bainbridge, who had the unusual qualification of being a physicist with undergraduate training in electrical engineering. He was quiet and competent and had the respect and liking of the over two hundred enlisted men later on duty at Alamogordo. His first step, with the assistance of Oppenheimer, Major W. A. Stevens, who was in charge of construction activities at Los Alamos, and Major Peer DeSilva, the head of security at Los Alamos, was to select a site.
I had ruled out using Los Alamos for the test on grounds of security and also because I doubted if the area could be expanded sufficiently. Later, we decided that we would need a site measuring approximately seventeen by twenty-four miles, that it should be in a generally non-populated area, and that it should be no further from Los Alamos than necessary. I added one special prohibition: that it should have no Indian population at all, for I wanted to avoid the impossible problems that would have been created by Secretary of the Interior Harold L. Ickes, who had jurisdiction over the Bureau of Indian Affairs. His curiosity and insatiable desire to have his own way in every detail would have caused difficulties and we already had too many.
After looking at several other sites, the committee finally settled on Alamogordo as being entirely satisfactory. It was on an air base, but was far removed from the airfield itself. Arrangements were promptly made with Major General U. G. Ent, under whose control the base came, for us to use the Alamogordo area.
We were not sure until the last moment exactly when we would be ready. The time depended entirely upon the delivery and successful assembly of the bomb’s components. I felt that I had to be present personally, especially in case anything went wrong, and naturally Bush and Conant wanted to be there, too.
Because of our uncertainty about the date, the three of us decided to visit several of the MED’s installations on the Pacific Coast during the days preceding the test. This would enable us to get to Alamogordo promptly if the date of the test were advanced. We went first to Hanford; from Hanford to San Francisco, where we visited the Berkeley Laboratory; from San Francisco to Inyokern; then to Pasadena; and from there to Albuquerque, where we switched from plane to automobile and drove to Alamogordo.
Air travel has improved considerably since those days. The field we used at Pasadena was very small, and our approach to it was impeded by some high-tension lines at the end of the strip. As he came in, our pilot found himself lined up on the taxiway and quite low. Instead of circling the field, he came in over the wires and then side-slipped, landing with a terrific bounce—both horizontal and vertical. Our landing brought everyone out of the small operations office, including one of my security officers who had missed the plane in San Francisco, and who was waiting to rejoin us in Pasadena. He remarked afterward that, if not the first, at least the second thought that flashed through his mind was: “How am I going to explain the accidental death of Bush, Conant and Groves, without publicity to the project and resulting breaches of security?”
We left the next morning from March Field in Riverside in order to be sure that the predicted Los Angeles fog would not interfere with our taking off. One of the members of our plane crew had been telling me for several days that he was looking forward to spending a night in Los Angeles so that he could see his mother. After we were airborne again, I asked him: “Did you see your mother all right?” He replied, “No, sir, I didn’t dare go and see her because she has always worried about my flying, and I knew that after yesterday’s landing I would not sound too convincing about its safety.”
After arriving at the Alamogordo base camp on July 15, a brief review of the situation with Oppenheimer revealed that we might be in trouble. The bomb had been assembled and placed at the top of its hundred-foot-high steel tower, but the weather was distinctly unfavorable. There was an air of excitement at the camp that I did not like, for this was a time when calm deliberation was most essential. Oppenheimer was getting advice from all sides on what should and should not be done. After discussing matters with General Farrell, who had been there for several days, I concluded that the best thing I could do was to introduce as much of an atmosphere of calm as possible into the very tense situation.
The main problem was the weather. We had obtained the very best men that the armed forces had on long-range weather forecasting, and, for a considerable period, they had been making accurate long-range weather predictions for the test site. The only time they were not right was on the one day that counted. The weather that evening was quite blustery and misty, with some rain. Fortunately, the wind seemed to be in the right direction.
We were interested in the weather for a number of reasons: First and foremost, we wanted to avoid as much radioactive fallout2 as possible, particularly over populated areas. This was a matter that had not received any attention until about six months earlier, when one of the Los Alamos scientists, Joseph Hirschfelder, had brought up the possibility that it might be a real problem. For this reason, we felt it would be desirable to explode the bomb when rain was unlikely, since rain would bring down excessive fallout over a small area instead of permitting it to be widely distributed and therefore of little or no consequence. In reaching this decision we could not ignore the old reports that heavy battle cannonading had sometime brought on rain, even though no scientific basis was known for an such phenomenon.
Second, it was extremely important that the wind direction be satisfactory, because we did not want the cloud, if one developed, to pass over any populated areas until its radioactive contents were thoroughly dissipated. It was essential that it not pass over any town too large to be evacuated. The city about which we were most concerned was Amarillo, some three hundred miles away, but there were others large enough to cause us worry. The wind direction had to be correct to within a few degrees.
Third, we wanted suitable flying weather so that we could have observation planes flying over the near-by areas; and finally, we wanted to avoid prior heavy rain or continuous dampness, which might ruin our electrical connections, both for firing the bomb, and for the various instruments.
Many of Oppenheimer’s advisers at the base camp (and by 6 p.m. these included not only the senior scientists, but many in secondary positions) were urging that the test be postponed for at least twenty-four hours.3 I felt that no sound decision could ever be reached amidst such confusion, so I took Oppenheimer into an office that had been set up for him in the base camp, where we could discuss matters quietly and calmly. The only other persons taking part in this conversation were some weather forecasters whom we called in. Since it was obvious that they were completely upset by the failure of the long-range predictions, I soon excused them. After that, it was necessary for me to make my own weather predictions—a field in which I had nothing more than very general knowledge.
I was extremely anxious to have the test carried off on schedule. One reason for this was that I knew the effect that a successful test would have on the issuance and wording of the Potsdam ultimatum. I knew also that every day’s delay in the test might well mean the delay of a day in ending the war; not because we would not be ready with the bombs, for the production of fissionable material would continue at full tilt anyway, but because a delay in issuing the Potsdam ultimatum could result in a delay in the Japanese reaction, with a further delay to the atomic attack on Japan. Obviously, a reasonable time had to be allowed for the Japanese to consider the ultimatum.
From a purely technical point of view, also, it was desirable to avoid a postponement, for the chances of short circuits and a misfire would increase appreciably with every hour that our connections were subjected to excessive moisture. To an even greater degree, though not of such vital importance to the test, the connections to and within our instruments, which naturally had not been so carefully put together as those for the bomb, would be subject to damage. I also recognized the concern of our security officers that every hour of delay would increase the possibility of someone’s attempting to sabotage the tests. The strain had been great on all our people, and it was impossible to predict just when someone might give way under it. There was always the chance, too, that a trained saboteur might be present, either within or without our organization, awaiting his opportunity.
At the end of our discussion, Oppenheimer and I agreed that there was no need to postpone the test for a day, but that we might have to put it off for an hour or two.
It had originally been scheduled for 4 a.m. on July 16. This hour had been fixed with the thought that an explosion at that time would attract the least attention from casual observers in the surrounding area, since almost everyone would be asleep. We expected there would be a tremendous flash of light, but thought it would not be great enough to waken many people who were well removed from the burst. Then, too, we wanted the darkness for our photography.
Oppenheimer and I agreed to meet again at 1 a.m., and to review the situation then, with the understanding that we should be ready to set the bomb off on schedule if the weather had improved by that time. I urged Oppenheimer to go to bed and to get some sleep, or at least to take a rest, and I set the example by doing so myself. Oppenheimer did not accept my advice and remained awake, I imagine constantly worrying. Bush, Conant and I were quartered in a tent that had not been set up very well and the canvas slapped constantly in the high wind. Bush and Conant told me afterward that they could not sleep at all, and did not understand how I could under such conditions.
About 1 A.M., Oppenheimer and I went over the situation again, and decided to leave the base camp, which was ten miles from the bomb, and go up to the control dugout, which was about five miles away. The only people at the control dugout were those whose duties required them to be there. I had arranged for Farrell to be at this point during the test, while I would be at the base camp, the nearest point to the explosion where we permitted anyone to be out in the open. Although there was an air of excitement at the dugout, there was a minimum of conflicting advice and opinions. This was because everyone there had something to do, checking and rechecking the equipment under their control.
As the hour approached, we had to postpone the test—first for an hour and then later for thirty minutes more—so that the explosion was actually three and one half hours behind the original schedule. While the weather did not improve appreciably, neither did it worsen. It was cloudy with light rain and high humidity; very few stars were visible. Every five or ten minutes, Oppenheimer and I would leave the dugout and go outside and discuss the weather. I was devoting myself during this period to shielding Oppenheimer from the excitement swirling about us, so that he could consider the situation as calmly as possible, for the decisions to be taken had to be governed largely by his appraisal of the technical factors involved.
Shortly before we determined the hour that the test would go ahead, we received word from Captain Parsons, who was at the Albuquerque Airfield ready to take off in one of the observation planes, that the Base Commander objected to planes’ flying in the area because of weather conditions. I decided that we would hold the test whether the planes were allowed to take off or not. Actually they did take off, but because of the weather their observations were not of as great value as we had hoped. The main reason for having observation planes in the air was to enable Parsons to report later on the relative visual intensity of the explosion of the test bomb and that of the one we would drop on Japan.
Once the decision was made to go ahead, no additional orders were needed. At thirty minutes before the zero hour, the five men who had been guarding the bomb to make certain that no one tampered with it left their point of observation at the foot of the tower. They came back to the dugout by jeeps,4 reaching there in ample time. Their instructions were very definite about what they should do in case of motor trouble, and since Kistiakowsky was one of the five, I knew that they would find a safe position even in the event of a complete breakdown. After all, in the thirty minutes allotted for their return they could walk several miles from the point of detonation, and I was sure that they would not walk slowly. They also had the key to a padlock guarding the firing circuit at the dugout. Nevertheless, if they had not come back in time, we would have had a real problem, particularly if we had no idea where they were. Fortunately, the problem did not arise. As they left the bomb tower, previously emplaced large lights were turned on as a marker for the observing planes. They also illuminated the tower so that it could be seen with field glasses from the vicinity of the dugout. This, we felt, would serve as a deterrent to any but the most courageous saboteur.
A little later, leaving Oppenheimer at the dugout, I returned to the base camp. There was quite a hubbub of excitement there, but not too much tension. Most of these people had spent many months and even years in preparation for this moment, but now they had no further responsibility for the conduct of any part of the actual test.
Our preparations here were simple. Everyone was told to lie face down on the ground, with his feet toward the blast, to close his eyes, and to cover his eyes with his hands as the countdown approached zero. As soon as they became aware of the flash they could turn over and sit or stand up, covering their eyes with the smoked glass with which each had been supplied. We thought that the time necessary for this movement would be sufficient to eliminate any danger of eye injury. As we approached the final minute, the quiet grew more intense. I, myself, was on the ground between Bush and Conant. As I lay there, in the final seconds, I thought only of what I would do if, when the countdown got to zero, nothing happened.
I was spared this embarrassment, for the blast came promptly with the zero count, at 5:30 A.M., on July 16, 1945.
My first impression was one of tremendous light, and then as I turned, I saw the now familiar fireball. As Bush, Conant and I sat on the ground looking at this phenomenon, the first reactions of the three of us were expressed in a silent exchange of handclasps. We all arose so that by the time the shock wave arrived we were standing.
I was surprised by its comparative gentleness when it reached us almost fifty seconds later. As I look back on it now, I realize that the shock was very impressive, but the light had been so much greater than any human had previously experienced or even than we had anticipated that we did not shake off the experience quickly.
Unknown to me and I think to everyone, Fermi was prepared to measure the blast by a very simple device. He had a handful of torn paper scraps and, as it came time for the shock wave to approach, I saw him dribbling them from his hand toward the ground. There was no ground wind, so that when the shock wave hit it knocked some of the scraps several feet away. Since he dropped them from a fixed elevation from near his body which he had previously measured, the only measurement he now needed was the horizontal distance that they had traveled. He had already calculated in advance the force of the blast for various distances. So, after measuring the distance on the ground, he promptly announced the strength of the explosion. He was remarkably close to the calculations that were made later from the data accumulated by our complicated instruments.
I had become a bit annoyed with Fermi the evening before, when he suddenly offered to take wagers from his fellow scientists on whether or not the bomb would ignite the atmosphere, and if so, whether it would merely destroy New Mexico or destroy the world. He had also said that after all it wouldn’t make any difference whether the bomb went off or not because it would still have been a well worth-while scientific experiment. For if it did fail to go off, we would have proved that an atomic explosion was not possible. Afterward, I realized that his talk had served to smooth down the frayed nerves and ease the tension of the people at the base camp, and I have always thought that this was his conscious purpose. Certainly, he himself showed no signs of tension that I could see. There was at least one member of the project who was completely unprepared for the events of that morning. He was an enlisted man—a cook, I believe. He had returned from pass during the evening and, as it was afterward reported to me, had possibly had a bit too much to drink. Somehow, the military police in searching the barracks before the explosion had missed him and he was lying in his bunk, half-asleep, when the explosion came. It blinded him temporarily, but after a few days he was perfectly all right. There were many stories afterward about his determination never to take another drink.
Another casualty of the explosion was Jumbo. At the time of the blast it was standing on end some five hundred yards away from the tower. The explosion knocked it into a slanting position, where it remained for years as a silent witness to the power of the infinitesimal atom.
I had planned to remain at Alamogordo for a number of hours after the explosion to make certain that there was no fallout problem. In order to make full use of the time, I planned to discuss and settle a number of matters involved in our operations against Japan with the members of the Los Alamos group, some of whom were due to leave almost immediately for Tinian. I had also counted on having a discussion with Oppenheimer on some other important points. These plans proved utterly impracticable, for no one who had witnessed the test was in a frame of mind to discuss anything. The reaction to success was simply too great. It was not only that we had achieved success with the bomb; but that everyone—scientists, military officers and engineers—realized that we had been personal participants in, and eyewitnesses to, a major milestone in the world’s history and had a sobering appreciation of what the results of our work would be. While the phenomenon that we had just witnessed had been seriously discussed for years, it had always been thought of as a remote possibility—not as an actuality.
Shortly after the explosion, Farrell and Oppenheimer returned by jeep to the base camp, with a number of the others who had been at the dugout. When Farrell came up to me, his first words were, “The war is over.” My reply was, “Yes, after we drop two bombs on Japan.” I congratulated Oppenheimer quietly with “I am proud of all of you,” and he replied with a simple “Thank you.” We were both, I am sure, already thinking of the future and whether we could repeat our success soon and bring the war to an end.
I soon decided that the most useful thing I could do was to make certain that the other phases of the operation were going smoothly, and my first concern was with the steps that were being taken to ensure that no damage resulted from fallout. This was the responsibility of our Chief Medical Officer, Colonel Stafford Warren, who had made elaborate preparations for gathering data and for the conduct of our safety precautions.
My greatest concern was over radioactive fallout and the possibility that it might concentrate on a populated area or even an isolated ranch. We had a network of carefully instructed men equipped with Geiger counters who observed the moving cloud as long as they could see it and took repeated Geiger counter readings after it had passed. These were reported back to us at Alamogordo.
As it happened, all went well, but if there had been excessive fallout that would have made it necessary to move out any civilians, we had provided for the emergency. We had military trucks standing by. We were also fully prepared to have martial law declared over as large an area as might be necessary. Naturally, the likelihood that any such action would be required decreased as the distance from the explosion site increased. The first reports began coming in within about half an hour after the explosion and throughout the next critical three hours we had a good picture of the situation at all times.
When I went to Warren’s headquarters in the base camp soon after the explosion, I was not pleased to discover that he had been so busy getting ready that he had gone without sleep for almost forty-eight hours. Although his decisions were sound and his instructions were clear, I was sure from listening to them as he talked over the telephone, that—quite understandably—his mind was not working so quickly as it normally did, by any means. Fortunately, we had at Alamogordo a Navy doctor who was familiar with our activities—Captain George Lyons, and I suggested that he spell Warren for a few hours to give him some rest. I was displeased, too, with myself, because I felt that I had fallen down in not making certain that Warren would be in first-class physical shape to handle the situation. However, as the reports came in, it was evident that we would probably have no trouble.
At about 11 a.m., a major security problem arose. We had stationed at the Associated Press office in Albuquerque an officer whose job was to keep any alarming dispatches on the explosion from going out. Shortly before eleven, the AP man told our officer that he could no longer hold back on the story; that, if there was nothing put out by the Army, he would have to put his own stories on the wire. This was relayed to me from Albuquerque.
We had prepared for an official release weeks before by having General R. B. Williams, who had replaced General Ent in command of the Air Forces in that area, and who also had administrative control over the Wendover Base and the 509th Group, write a letter to the Commanding Officer of the Alamogordo Air Base. This letter was delivered in person by Lieutenant W. A. Parish, Jr., from my office, a very smooth young Texas lawyer whose calm, unfailing courtesy and great firmness in carrying out his instructions had been my reason for picking him for this assignment. He had no difficulty whatever in adapting himself to a situation and getting the job done.
The letter said merely that the Commanding Officer would carry out any instructions that the Lieutenant might give him. Naturally, his first query when the letter was presented to him was: “What is it all about?” Parish replied: “I am sorry, Colonel, I cannot tell you.” That this was not all pleasing to the Colonel is an understatement, according to the account I received from Parish. The Colonel next asked what the instructions would be and received the same reply. As it was reported to me, both General Williams and his ways of doing business, as well as ours, were most severely criticized. The Colonel then said that he did not wish to have anything to do with the matter, so he would turn Parish over to his Executive Officer, whom he told to carry out General Williams’ directions.
My only means of communicating with him was by an open telephone circuit. He had been told the afternoon before that the test would probably take place during the night. Later he was told that all planes at Alamogordo Base should be held on the ground until further notice. Arrangements had also been made with the Civil Aeronautics Authority, as well as with the Air Force and Navy, to ensure that the entire area would be barred to all aircraft during the crucial hours. This was quite upsetting to the base, for it was there that regular B-29 crews received their final training before leaving for the Pacific Theater. Every unit commander wanted his crews to have as many hours in the air as possible, and time was always at a premium. All that the people on the base knew was that their training schedules were being upset for some unexplained reason.
During the early morning hours of the sixteenth, the Executive Officer and Parish stayed at the air control tower at the base. The Executive Officer was most co-operative, apparently fully appreciating the difficult position in which Parish found himself. There was never any question of “Why?” Simply: “What do you want me to do now?” Many men were already on the landing field when the explosion occurred, and not long after several thousand men were there preparing for take-offs. After a reasonable wait the aircraft were released and training resumed without too much harm having been done.
Parish had been provided with a release to be issued by the Commanding Officer at Alamogordo Base. Every word in this release was numbered, so that it was a simple matter to alter it without disclosing any secrets to an unauthorized listener-in. When the AP man at Albuquerque became insistent, I telephoned to Parish and made the necessary deletions and insertions in the release, and told him to have it given out at once. It read:
ALAMOGORDO, N.M., July 16
The commanding officer of the Alamogordo Army Air Base made the following statement today:
“Several inquiries have been received concerning a heavy explosion which occurred on the Alamogordo Air Base reservation this morning.
“A remotely located ammunition magazine containing a considerable amount of high explosives and pyrotechnics exploded.
“There was no loss of life or injury to anyone, and the property damage outside of the explosives magazine itself was negligible.
“Weather conditions affecting the content of gas shells exploded by the blast may make it desirable for the Army to evacuate temporarily a few civilians from their homes.”
In the meantime, a great deal of excitement had swept the civilian community throughout New Mexico, and particularly in El Paso, Texas. With the usual freakiness of such explosions, the bomb had done little damage at the base camp, or anywhere else near by, but had cracked one or two plate-glass windows at Silver City, New Mexico, 180 miles away. The El Paso papers carried banner headlines of the explosion and the phenomena occurring in that area.
Through the close supervision and co-operation of the Office of Censorship under Byron Price and Jack Lockhart, no news of the explosion appeared in any Eastern paper, except for a few lines in the early morning edition of a Washington paper. On the Pacific Coast, however, it got on the radio, and spread up and down the Coast.
One disturbing element in our preparations for the press release, and the reason I had held it up for so long, was our uncertainty whether we would have to evacuate some of the civilian population. Because of this possibility, when I talked to Parish I inserted the reference to gas shells.
Our release did not fool everybody. Several days after I got back to Washington, Dr. R. M. Evans, of the du Pont Company, came to see me about some of the operating problems at Hanford. After we had finished and as he was leaving, he turned, his hand on the doorknob, and said, “Oh, by the way, General, everybody in du Pont sends you their congratulations.” I quickly replied, “What are you talking about?” He answered, “It’s the first time we ever heard of the Army’s storing high explosives, pyrotechnics and chemicals in one magazine.” He went on to add that the radio announcement on the Pacific Coast had been teletyped in to Wilmington from Hanford. My only response was: “That was a strange thing for the Army to do, wasn’t it?”
Mrs. O’Leary, my secretary, had been told the day before the test to be in the office by 6:30 the next morning to receive a message. Because of the delay in the test, I could not telephone her until after 7:30 Washington time. I had left with her a special code sheet which I would use to pass on the results of the test either by telephone or by teletype. In addition, I made use of another code, of which only she and I had copies, so that I could safely talk to her over the telephone. In my message to her, I gave her the salient facts which should be reported by cable to the Secretary of War at Potsdam.
Before his departure for Potsdam, Secretary Stimson had set up a special channel of communication between himself and me when he designated George L. Harrison as his representative in Washington to cover atomic affairs. This arrangement not only made it possible for the Secretary and me to get in touch with each other quickly, but it also was a security safeguard. A cable, and particularly a number of them, between the Secretary and me would have aroused considerable curiosity in the Army’s communications center, and thus would have increased our security hazards. As soon as Mrs. O’Leary finished decoding my message she went over to the Pentagon to Harrison’s office. She showed him the message and helped him draft the first cables to Mr. Stimson.
When it became clear late in the afternoon that radioactive fallout was not going to be a problem, I started my plane trip back to Washington with Bush, Conant, Lawrence and Tolman. They were still upset by what they had seen and could talk of little else. I learned later that the effects of the test on all who had witnessed it, particularly the scientists, were quite profound for a number of days. As for me, my thoughts were now completely wrapped up with the preparations for the coming climax in Japan.
Upon my arrival in Washington, at about noon on the day after the test, I talked to Harrison and we followed up his previous cable to Mr. Stimson with another one. The next day in the early afternoon he suggested that it would be a good idea if I wrote a full report and sent it over by courier to the Secretary at Potsdam. I agreed, for I realized that the cables, because of their guarded brevity, had not given Mr. Stimson as much information as he might need.
Because of various uncancelable appointments, I could not work on the report that afternoon. When I learned that the courier was scheduled to leave for Potsdam the following morning at about two o’clock, I made arrangements to hold the plane until the report was ready. After writing the first paragraph, which set the general tone, I outlined to Farrell the ground it should cover. This enabled him to start at once on the first draft of the report as well as to write the section that was to be attributed to him.
At about 6:30 that night I started on the balance of the draft and went over with Farrell the part he had written. After we had completed a rough draft, we revised it and then continued to polish it throughout the evening.
Because it was so highly secret, only Mrs. O’Leary and one other fully cleared secretary were allowed to do any of the typing. They had been at work since eight o’clock that morning with only two short breaks for lunch and for sandwiches in the early evening, and by midnight, when the final draft was ready, they were so tired that every page was torture. Shortly after two o’clock the report was finally ready and signed, and was then taken directly to the courier plane.5
In Potsdam it was delivered to Colonel Kyle, Mr. Stimson’s aide, who placed it in his hands at 11:35 a.m. on July 21. He and Harvey Bundy read it immediately, and then made the earliest possible appointment with President Truman, for 3:30. At 3:00, finding that General Marshall was available, the Secretary had him read it and talked with him about it. He then went over to the President’s house and read it to Mr. Truman and Secretary Byrnes. After that, accompanied by Bundy, he conferred with Churchill and Lord Cherwell. This conference was soon interrupted but was resumed the next morning, when Churchill read the complete report for the first time. Mr. Stimson’s diary for Sunday, July 22, 1945, is most enlightening:
Churchill read Groves’ report in full. He told me that he had noticed at the meeting of the Three yesterday that Truman was much fortified by something that had happened, that he had stood up to the Russians in a most emphatic and decisive manner, telling them as to certain demands that they could not have and that the United States was entirely against them. He said, “Now I know what happened to Truman yesterday. I couldn’t understand it. When he got to the meeting after having read this report, he was a changed man. He told the Russians just where they got on and off and generally bossed the whole meeting.” Churchill said he now understood how this pepping up had taken place and he felt the same way.
The receipt of the news of the successful test at Alamogordo and the reassurance that we would be ready for the first bombing of Japan on July 31, weather permitting, froze the previously tentative decision that it was now time to issue the Potsdam ultimatum to Japan. Just how differently the ultimatum would have been worded without this knowledge, no one knows, but with the news of our success in hand President Truman and Mr. Churchill were able to see it dispatched with a great deal more confidence than otherwise might have been the case.
1 Its dimensions were as follows: Inside diameter, 10 feet; straight length between the heads, 25 feet. It had an intershell 6 inches thick of solid steel plate. The shell, after the attachment of the two closure heads by welding, was banded with a number of layers of %-inch-thick steel bands, so that the overall thickness of the main part of the shell was approximately 14 inches.
2 Radioactive fallout is the falling to earth of particles of airborne matter which have been made radioactive through the effects of a nuclear explosion. These are of varying danger to life, depending on how long they retain a high degree of radioactivity; the time varies greatly with the different elements, from seconds to many decades (for one isotope of cobalt). With the bomb explosive only one hundred feet off the ground, we expected that a great deal of material from the tower and the ground surrounding it would be made radioactive and carried as small particles for great distances though the air.
3 I found out later that Bainbridge and his principal associates who were at the bomb tower did not want a postponement. The weather seemed better at that point. One of them, R. B. Wilson, insisted that if the shot was postponed, it would be days before it could be made, for the key personnel were completely worn out and would have to have a rest before starting the necessary checks again. I think he was right.
4 In a previous check test with a hundred tons of TNT, a jeep had broken down. This time, to be on the safe side, they were using several.
5 See Appendix VIII, page 433.