Manhattan Project

Just before the First World War, two German scientists, James Franck and Gustav Hertz, carried out experiments where they bombarded mercury atoms with electrons and traced the energy changes that resulted from the collisions. Their experiments helped to substantiate they theory put forward by Nils Bohr that an atom can absorb internal energy only in precise and definite amounts.

In 1921 two Otto Hahn and Lise Meitner, discovered nuclear isomers. Over the next few years they devoted their time to researching the application of radioactive methods to chemical problems. In the 1930s they became interested in the research being carried out by Enrico Fermi and Emilio Segre at the University of Rome. This included experiments where elements such as uranium were bombarded with neutrons. By 1935 the two men had discovered slow neutrons, which have properties important to the operation of nuclear reactors.

Otto Hahn and Lise Meitner were now joined by Fritz Strassmann and discovered that uranium nuclei split when bombarded with neutrons. In 1938 Meitner, like other Jews in Nazi Germany, was dismissed from her university post. She moved to Sweden and later that year she wrote a paper on nuclear fission with her nephew, Otto Frisch, where they argued that by splitting the atom it was possible to use a few pounds of uranium to create the explosive and destructive power of many thousands of pounds of dynamite.

In January, 1939 a Physics Conference took place in Washington in the United States. A great deal of discussion concerned the possibility of producing an atomic bomb. Some scientists argued that the technical problems involved in producing such a bomb were too difficult to overcome, but the one thing they were agreed upon was that if such a weapon was developed, it would give the country that possessed it the power to blackmail the rest of the world. Several scientists at the conference took the view that it was vitally important that all information on atomic power should be readily available to all nations to stop this happening.

On 2nd August, 1939, three Jewish scientists who had fled to the United States from Europe, Albert Einstein, Leo Szilard and Eugene Wigner, wrote a joint letter to President Franklin D. Roosevelt, about the developments that had been taking place in nuclear physics. They warned Roosevelt that scientists in Nazi Germany were working on the possibility of using uranium to produce nuclear weapons. Roosevelt responded by setting up a scientific advisory committee to investigate the matter. He also had talks with the British government about ways of sabotaging the German efforts to produce nuclear weapons.

In May, 1940, the German Army invaded Denmark, the home of Niels Bohr, the world's leading expert on atomic research. It was feared that he would be forced to work for Nazi Germany. With the help of the British Secret Service he escaped to Sweden before being moving to the United States.

In 1942 the Manhattan Engineer Project was set up in the United States under the command of Brigadier General Leslie Groves. Scientists recruited to produce an atom bomb included Robert Oppenheimer (USA), David Bohm (USA), Leo Szilard (Hungary), Eugene Wigner (Hungary), Rudolf Peierls (Germany), Otto Frisch (Germany), Niels Bohr (Denmark), Felix Bloch (Switzerland), James Franck (Germany), James Chadwick (Britain), Emilio Segre (Italy), Enrico Fermi (Italy), Klaus Fuchs (Germany) and Edward Teller (Hungary).

Winston Churchill and Franklin D. Roosevelt were deeply concerned about the possibility that Germany would produce the atom bomb before the allies. At a conference held in Quebec in August, 1943, it was decided to try and disrupt the German nuclear programme. In February 1943, SOE saboteurs successfully planted a bomb in the Rjukan nitrates factory in Norway. As soon as it was rebuilt it was destroyed by 150 US bombers in November, 1943. Two months later the Norwegian resistance managed to sink a German boat carrying vital supplies for its nuclear programme.

Meanwhile the scientists working on the Manhattan Project were developing atom bombs using uranium and plutonium. The first three completed bombs were successfully tested at Alamogordo, New Mexico on 16th July, 1945. James Chadwick later described what he saw during the test: "An intense pinpoint of light which grew rapidly to a great ball. Looking sideways, I could see that the hills and desert around us were bathed in radiance, as if the sun had been turned on by a switch. The light began to diminish but, peeping round my dark glass, the ball of fire was still blindingly bright ... The ball had then turned through orange to red and was surrounded by a purple luminosity. It was connected to the ground by a short grey stem, resembling a mushroom."

By the time the atom bomb was ready to be used Germany had surrendered. James Franck and Leo Szilard drafted a petition signed by just under 70 scientists opposed to the use of the bomb on moral grounds. Franck pointed out in his letter to Truman: "The military advantages and the saving of American lives achieved by the sudden use of atomic bombs against Japan may be outweighed by the ensuing loss of confidence and by a wave of horror and repulsion sweeping over the rest of the world and perhaps even dividing public opinion at home. From this point of view, a demonstration of the new weapon might best be made, before the yes of representatives of all the United Nations, on the desert or a barren island. The best possible atmosphere for the achievement of an international agreement could be achieved if America could say to the world, "You see what sort of a weapon we had but did not use. We are ready to renounce its use in the future if other nations join us-in this renunciation and agree to the establishment of an efficient international control."

However, the advice of the scientists was ignored by Harry S. Truman, the USA's new president, and he decided to use the bomb on Japan. General Dwight Eisenhower agreed with the scientists: "I voiced to him my grave misgivings, first on the basis of my belief that Japan was already defeated and that dropping the bomb was completely unnecessary, and secondly because I thought that our country should avoid shocking world opinion by the use of a weapon whose employment was, I thought, no longer mandatory as a measure to save American lives. It was my belief that Japan was, at that very moment, seeking some way to surrender with a minimum loss of face."

At Yalta, the Allies had attempted to persuade Joseph Stalin to join in the war with Japan. By the time the Potsdam meeting took place, they were having doubts about this strategy. Winston Churchill in particular, were afraid that Soviet involvement would lead to an increase in their influence over countries in the Far East. On 17th July 1945 Stalin announced that he intended to enter the war against Japan.

President Truman now insisted that the bomb should be used before the Red Army joined the war against Japan. Leslie Groves, the head of the Manhattan Project, wanted the target to be Kyoto because as it had been untouched during previous attacks, the dropping of the atom bomb on it would show the destructive power of the new weapon. However, the Secretary of War, Henry Stimson, argued strongly against this as Kyoto was Japan's ancient capital, a city of immense religious, historical and cultural significance. General Henry Arnold supported Stimson and Truman eventually backed down on this issue.

President Truman wrote in his journal on 25th July, 1945: "This weapon is to be used against Japan between now and August 10th. I have told the Secretary of War, Mr Stimson, to use it so that military objectives and soldiers and sailors are the target and not women and children. Even if the Japs are savages, ruthless, merciless and fanatic, we, as leader of the world for the common welfare cannot drop this terrible bomb on the old capital or the new. He & I are in accord. The target will be a purely military."

Truman's military advisers accepted that Kyoto would not be targeted but insisted that another built-up area should be chosen instead: "While the bombs should not concentrate on civilian areas, they should seek to make a profound a psychological impression as possible. The most desirable target would be a vital war plant employing a large number of workers and closely surrounded by workers' houses."

Winston Churchill insisted that two British representives should witness the dropping of the atom bomb. Squadron Leader Leonard Cheshire and William Penny, a scientist working on the Manhattan Project, were chosen for this task. Churchill ordered them to learn "about the taqctical aspects of using such a weapon, reach a conclusion about its future implications for air warfare and report back to the Prime Minister."

General Thomas Farrell, Commander of the Manhattan Project, explained to Cheshire and Penny that they had produced two types of bomb. Fat Man relied upon implosion: a 12 lb sphere of plutonium would be abruptly squeezed to super-critically by the detonation of an envelope of explosive. Little Boy functioned by a gun mechanism which fired two subcritical masses of uranium 235 together.

President Harry S. Truman eventually decided that the bomb should be dropped on Hiroshima. It was the largest city in the Japanese homeland (except Kyoto) which remained undamaged, and a place of military industry. However, Truman, after listening from advice of General Curtis LeMay, refused permission for Leonard Cheshire and William Penny to witness the event. Leslie Groves, according to Cheshire, "said firmly that there was no room for either of us; in any case he couldn't see why we needed to be there, for we would receive a full written report and could ask to see any documentation we wanted."

On 6th August 1945, a B29 bomber piloted by Paul Tibbets, dropped an atom bomb on Hiroshima. Michihiko Hachiya was living in the city at the time: "Hundreds of people who were trying to escape to the hills passed our house. The sight of them was almost unbearable. Their faces and hands were burnt and swollen; and great sheets of skin had peeled away from their tissues to hang down like rags or a scarecrow. They moved like a line of ants. All through the night, they went past our house, but this morning they stopped. I found them lying so thick on both sides of the road that it was impossible to pass without stepping on them."

Later that day President Harry S. Truman made a speech where he argued: "The harnessing of the basic power of the universe. The force from which the sun draws its power has been used against those who brought war to the Far East. We have spent $2,000,000,000 (about $500,000,000) on the greatest gamble in history, and we have won. With this bomb we have now added a new and revolutionary increase in destruction to supplement the growing power of our armed forces. In their present form these bombs are now in production and even more powerful forms are in development."

Truman then issued a warning to the Japanese government: "We are now prepared to obliterate more rapidly and completely every productive enterprise the Japanese have above ground in any city. We shall destroy their docks, their factories and their communications. Let there be no mistake, we shall completely destroy Japan's power to make war. It was to spare the Japanese people from utter destruction that the ultimatum of July 26 was issued from Potsdam. Their leaders promptly rejected that ultimatum. If they do not now accept our terms they may expect a rain of run from the air the like of which has never been seen on this earth. Behind this air attack will follow sea and land forces in such numbers and power as they have not yet seen and with a fighting skill of which they have already become well aware."

Hideki Tojo, Japan's Foreign Minister, told Emperor Hirohito on 8th August, 1945, that Hiroshima had been obliterated by an atom bomb and advised surrender. Others raised doubts about whether the United States had more than one of these bombs. The Supreme Council decided to convene a meeting on the morning of 9th August. As they had not immediately surrendered President Truman ordered that a second atom bomb should be dropped on Japan.

Major Charles Sweeney was selected to lead the mission and Nagasaki was chosen as the target. This time it was agreed that Leonard Cheshire and William Penny, could travel on the aircraft that was to take photographs of the attack on 9th August. When they reached Nagasaki they found the city covered in cloud and Kermit Beahan, the bombardier, was at first unable to find the target. Eventually, the cloud parted and Beahan dropped the bomb a mile and a half from the intended aiming point.

William Laurence was a journalist who was invited by Leslie Groves to be on Sweeney's aircraft: "We watched a giant pillar of purple fire, 10,000 feet high, shoot up like a meteor coming from the earth instead of outer space. It was no longer smoke, or dust, or even a cloud of fire. It was a living thing, a new species of being, born before our incredulous eyes. Even as we watched, a ground mushroom came shooting out of the top to 45,000 feet, a mushroom top that was even more alive than the pillar, seething and boiling in a white fury of creamy foam, a thousand geysers rolled into one. It kept struggling in elemental fury, like a creature in the act of breaking the bonds that held it down. When we last saw it, it had changed into a flower-like form, its giant petals curving downwards, creamy-white outside, rose-coloured inside. The boiling pillar had become a giant mountain of jumbled rainbows. Much living substance had gone into those rainbows."

Cheshire later recalled in his book, The Light of Many Suns (1985): "The ultra-dark glasses we each had round our foreheads to protect our eyes from the blinding light of the bomb were not needed because we were about fifty miles away. By the time I saw it, the flash had turned into a vast fire-ball which slowly became dense smoke, 2,000 feet above the ground, half a mile in diameter and rocketing upwards at the rate of something like 20,000 feet a minute. I was overcome, not by its size, nor by its speed of ascent but by what appeared to me its perfect and faultless symmetry. In this it was unique, above every explosion that I had ever heard of or seen, the more frightening because it gave the impression of having its immense power under full and deadly control.... The cloud lifted itself to 60,000 feet where it remained stationary, a good two miles in diameter, sulphurous and boiling. Beneath it, stretching right down to the ground was a revolving column of yellow smoke, fanning out at the bottom to a dark pyramid, wider at its base than was the cloud at its climax. The darkness of the pyramid was due to dirt and dust which one could see being sucked up by the heat. All around it, extending perhaps another mile, were springing up a mass of separate fires. I wondered what could have caused them all."

Fumiko Miura was a 16 year-old girl working in Nagasaki at the time: "I was doing some clerical work for the Japanese imperial army. At about 11 o'clock, I thought I heard the throbs of a B-29 circling over the two-storey army headquarters building. I wondered why an American bomber was flying around above us when we had been given the all-clear.... At that moment, a horrible flash, thousands of times as powerful as lightning, hit me. I felt that it almost rooted out my eyes. Thinking that a huge bomb had exploded above our building, I jumped up from my seat and was hit by a tremendous wind, which smashed down windows, doors, ceilings and walls, and shook the whole building. I remember trying to run for the stairs before being knocked to the floor and losing consciousness. It was a hot blast, carrying splinters of glass and concrete debris. But it did not have that burning heat of the hypocentre, where everyone and everything was melted in an instant by the heat flash. I learned later that the heat decreased with distance. I was 2,800m away from the hypocentre."

After a long debate Emperor Hirohito intervened and said he could no longer bear to see his people suffer in this way. On 15th August the people of Japan heard the Emperor's voice for the first time when he announced the unconditional surrender and the end of the war. Naruhiko Higashikuni was appointed as head of the surrender government.

© , September 1997 - April 2014

Primary Sources

(1) Lise Meitner and Otto Frisch, Uranium Fission (1938)

From chemical evidence, Hahn and Strassmann conclude that radioactive barium nuclei (atom number Z = 56) are produced when uranium (Z = 92) is bombarded by neutrons. It has been pointed out that this might be explained as a result of a "fission" of the uranium nucleus, similar to the division of a droplet into two. The energy liberated in such processes was estimated to be about 200 Mev, both from mass defect considerations and from the repulsion of the two nuclei resulting from the "fission" process.

If this picture is correct, one would expect fast-moving nuclei of atomic number 40 to 50 and atomic weight 100 to 150, and up to 100 Mev energy, to emerge from a layer of uranium bombarded with neutrons. In spite of their high energy, these nuclei should have a range in air of a few millimeters only, on account of their high effective charge (estimated to be about 20), which implies very dense ionization. Each such particle should produce a total of about 3 million ion pairs.

By means of a uranium-lined ionization chamber, connected to a linear amplifier, I have succeeded in demonstrating the occurrence of such bursts of ionization. The amplifier was connected to a thyratron which was biased so as to count only pulses corresponding to at least 5 x 105 ion pairs. About 15 particles per minute were recorded when 300 milligram of radium, mixed with beryllium, was placed one centimeter from the uranium lining. No pulses at all were recorded during repeated check runs of several hours total duration when either the neutron source or the uranium lining was removed. With the neutron source at a distance of four centimeters from the uranium lining, surrounding the source with paraffin wax enhanced the effect by a factor of two.

It was checked that the number of pulses depended linearly on the strength of the neutron source; this was done in order to exclude the possibility that the pulses are produced by accidental summation of smaller pulses. When the amplifier was connected to an oscillograph, the large pulses could be seen very distinctly on the background of much smaller pulses due to the alpha particles of uranium.

By varying the bias of the thyratron, the maximum size of pulses was found to correspond to at least 2 million ion pairs, or an energy loss of 70 Mev of the particle within the chamber. Since the longest path of a particle in the chamber was 3 centimeters, and the chamber was filled with hydrogen at atmospheric pressure, the particles must ionize so heavily that they can make 2 million ion pairs on a path equivalent to 0.8 cm of air or less. From this it can be estimated that the ionizing particles must have an atomic weight of at least about seventy, assuming a reasonable connection between atomic weight and effective charge. This seems to be conclusive physical evidence for the breaking up of uranium nuclei into parts of comparable size, as indicated by the experiments of Hahn and Strassmann.

Experiments with thorium instead of uranium gave quite similar results, except that surrounding the neutron source with paraffin did not enhance, but slightly diminished the effect. This gives evidence in favor of the suggestion that also in the case of thorium some, if not all of the activities produced by neutron bombardment, should be ascribed to light elements. It should be remembered that no enhancement by paraffin has been found for the activities produced in thorium, except for one which is isotopic with thorium and is almost certainly produced by simple capture of the neutron.

Meitner has suggested another interesting experiment. If a metal plate is placed close to a uranium layer bombarded with neutrons, one would expect an active deposit of the light atoms emitted in the "fission" of the uranium to form on the plate. We hope to carry out such experiments, using the powerful source of neutrons which our high-tension apparatus will soon be able to provide.

(2) On 2nd August, 1939, three Jewish scientist, Albert Einstein, Leo Szilard and Eugene Wigner, who had fled Nazi persecution in Europe, wrote a joint letter to President Franklin D. Roosevelt, about the developments that had been taking place in nuclear physics.

In the course of the last four months it has been made probable - through the work of Joliot in France as well as Fermi and Szilard in America - that it may become possible to set up a nuclear chain reaction in a large mass of uranium, by which vast amounts of power and large quantities of new radium-like elements would be generated. Now it appears almost certain that this could be achieved in the immediate future.

This new phenomenon would also lead to the construction of bombs, and it is conceivable - though much less certain - that extremely powerful bombs of a new type may thus be constructed. A single bomb of this type, carried by boat or exploded in a port, might well destroy the whole port together with some of the surrounding territory. However, such bombs might well prove to be too heavy for transportation by air.

(3) Niels Bohr, letter to President Franklin D. Roosevelt (3rd July, 1944)

A weapon of an unparalleled power is being created which will completely change all future conditions of warfare. Unless some agreement about the control of the use of the new active materials can be obtained in due time, any temporary advantage, however great, may be outweighed by a perpetual menace to human security. An initiative, aiming at forestalling a fateful competition, should serve to uproot any cause of distrust between the powers of whose harmonious collaboration the fate of coming generations will depend.

(4) Robert Oppenheimer, interviewed for a BBC television documentary, The Building of the Bomb, in 1965.

We were a true community of people working toward a common goal. I think that irrespective of what was done with it, irrespective of what was to come of it, it was clear that this was a very major change in the human situation, and the people were playing a part in history. We started out by thinking that it might make the difference between defeat and victory, and ended by thinking that it might make a difference between a world periodically convulsed by increasingly ferocious global wars and a world in which there will be none.

(5) Jim Tuck, a physical chemist at Manchester University joined the Manhattan Project. He was interviewed for a BBC television documentary, The Building of the Bomb, in 1965.

It had all the greatest scientists of the Western World, and something I'd never known before: they didn't care who you were, or what you were. All they cared-about was what you could contribute and what you had in the way of ideas. This was new to me. I met scientists I would never have expected to have seen in my whole life before.

(6) Philip Morrison, a scientist, worked on the Manhattan Project at Alamogordo, New Mexico. Studs Terkel interviewed Morrison about his experiences during the Second World War for his book, The Good War (1985)

We spent a lot of time and risked a lot of lives to do so. Of my little group of eight, two were killed. We were using high explosives and radioactive material in large quantities for the first time. There was a series of events that rocked us. We were working hard, day and night, to do something that had never been done before. It might not work at all. I remember working late one night with my friend Louis Slotin. He was killed by a radiation accident. We shared the job. It could have been I. But it was he, who was there that day.

James Franck, a truly wonderful man, produced the Franck Report: Don't drop the bomb on a city. Drop it as a demonstration and offer a warning. This was about a month before Hiroshima. The movement against the bomb was beginning among the physicists, but with little hope. It was strong at Chicago, but it didn't affect Los Alamos.

We heard the news of Hiroshima from the airplane itself, a coded message. When they returned, we didn't see them. The generals had them. But then the people came back with photographs. I remember looking at them with awe and terror. We knew a terrible thing had been unleashed. The men had a great party that night to celebrate, but we didn't go. Almost no physicists went to it. We obviously killed a hundred thousand people and that was nothing to have a party about. The reality confronts you with things you could never anticipate.

Before I went to Wendover, an English physicist. Bill Penney, held a seminar five days after the test at Los Alamos. He applied his calculations. He predicted that this would reduce a city of three or four hundred thousand people to nothing but a sink for disaster relief, bandages, and hospitals. He made it absolutely clear in numbers. It was reality. We knew it, but we didn't see it. As soon as the bombs were dropped, the scientists, with few exceptions, felt the time had come to end all wars.

(7) Robert Wilson, a member of the Manhattan Project team, suggested that the Allies should demonstrate the power of the atom bomb to a group of Japanese observers. He explained his views in a letter to R. W. Reid, the author of Tongues of Conscience (1970)

I made the suggestion fully aware-of the difference between a first use of a new weapon in which the blood of hundreds of thousands of men, women, and children would be on our hands, and of the dreadful precedent that would thereby be set - and that of illegally retaining, even executing, if you will, a few men. I realised by the dramatic character of the statement how far I had departed from the gentle pacifist of my student days. My regret in retrospect is not for the savagery of the remark, but rather that I did not use more forceful arguments with Oppenheimer in order to influence him to take more seriously my suggestion that some kind of a demonstration be made instead of the actual use.

(8) James Franck was against dropping the atom bomb on Japan. He sent his views to President Harry S. Truman on 11th June, 1945.

The military advantages and the saving of American lives achieved by the sudden use of atomic bombs against Japan may be outweighed by the ensuing loss of confidence and by a wave of horror and repulsion sweeping over the rest of the world and perhaps even dividing public opinion at home.

From this point of view, a demonstration of the new weapon might best be made, before the yes of representatives of all the United Nations, on the desert or a barren island. The best possible atmosphere for the achievement of an international agreement could be achieved if America could say to the world, "You see what sort of a weapon we had but did not use. We are ready to renounce its use in the future if other nations join us-in this renunciation and agree to the establishment of an efficient international control.

(9) Henry L. Stimson, The Decision to Use the Atom Bomb, Harper's Magazine (February, 1947)

The opinions of our scientific colleagues on the initial use of these weapons are not unanimous: they range from the proposal of a purely technical demonstration to that of the military application best designed to induce surrender. Those who advocate a purely technical demonstration would wish to outlaw the use of atomic weapons, and have feared that if we use the weapons now our position in future negotiations will be prejudiced. Others emphasise the opportunity of saving American lives by immediate military use, and believe that such use will improve the international prospects, in that they are more concerned with the prevention of war than with the elimination of this special weapon. We find ourselves closer to these latter views; we can propose no technical demonstration likely to bring an end to the war; we see no acceptable alternative to direct military use.

With regard to these general aspects of the use of atomic energy, it is clear that we, as scientific men, have no proprietary rights. It is true that we are among the few citizens who have had occasion to give thoughtful consideration to the problems during the past few years. We have, however, no claim to special competence in solving the political, social, and military problems which are presented by the advent of atomic power.

(10) Harry S. Truman, Year of Decisions (1955)

The task of creating the atomic bomb had been entrusted to a special unit of the Army Corps of Engineers, the so-called Manhattan District, headed by Major General Leslie R. Groves. The primary effort, however, had come from British and American scientists, working in laboratories and offices scattered throughout the nation.

Dr. J. Robert Oppenheimer, the distinguished physicist from the University of California, had set up the key establishment in the whole process at Los Alamos, New Mexico. More than any other one man, Oppenheimer is to be credited with the achievement of the completed bomb.

My own knowledge of these developments had come about only after I became President, when Secretary Stimson had given me the full story. He had told me at that time that the project was nearing completion and that a bomb could be expected within another four months. It was at his suggestion, too, that I had then set up a committee of top men and had asked them to study with great care the implications the new weapon might have for us.

At Potsdam, as elsewhere, the secret of the atomic bomb was kept closely guarded. We did not extend the very small circle of Americans who knew about it. Churchill naturally knew about the atomic bomb project from its very beginning, because it had involved the pooling of British and American technical skill.

On July 24th I casually mentioned to Stalin that we had a new weapon of special destructive force. The Russian Premier showed no unusual interest. All he said was that he was glad to hear it and hoped we would make "good use of it against the Japanese".

The final decision of where and when to use the atomic bomb was up to me. Let there be no mistake about it. I regarded the bomb as a military weapon and never had any doubt that it should be used.

(11) General Dwight Eisenhower, the Supreme Allied Commander, told President Harry S. Truman that he was opposed to the dropping of the atom bomb on Japan.

I voiced to him my grave misgivings, first on the basis of my belief that Japan was already defeated and that dropping the bomb was completely unnecessary, and secondly because I thought that our country should avoid shocking world opinion by the use of a weapon whose employment was, I thought, no longer mandatory as a measure to save American lives. It was my belief that Japan was, at that very moment, seeking some way to surrender with a minimum loss of face.

(12) William Leahy, chief of staff to the commander in chief of the United States, was opposed to the dropping of the atom bomb on Japan. He wrote about this in his autobiography, I Was There (1950)

Once it had been tested, President Truman faced the decision as to whether to use it. He did not like the idea, but was persuaded that it would shorten the war against Japan and save American lives. It is my opinion that the use of this barbarous weapon at Hiroshima and Nagasaki was of no material assistance in our war against Japan. The Japanese were already defeated and ready to surrender because of the effective sea blockade and the successful bombing with conventional weapons.

It was my reaction that the scientists and others wanted to make this test because of the vast sums that had been spent on the project. Truman knew that, and so did the other people involved. However, the Chief Executive made a decision to use the bomb on two cities in Japan. We had only produced two bombs at that time. We did not know which cities would be the targets, but the President specified that the bombs should be used against military facilities.

The lethal possibilities of atomic warfare in the future are frightening. My own feeling was that, in being the first to use it, we had adopted an ethical standard common to the barbarians of the Dark Ages. I was not taught to make war in that fashion, and wars cannot be won by destroying women and children. We were the first to have this weapon in our possession, and the first to use it. There is a practical certainty that potential enemies will develop it in the future and that atomic bombs will some time be used against us.

(13) Edward Teller was interviewed for a BBC television documentary, The Building of the Bomb, in 1965.

If we had made a demonstration and that had failed, then I think dropping the bomb would have been justified in order to end the war. To drop it without warning was wrong. It was wrong on moral grounds - it killed; it was wrong, although I could not see that at the time, on practical grounds because the dropping of the bomb has distorted our views, has changed our whole outlook. We are not now looking on the accomplishment of atomic explosions as progress which can, and should, be used in the right way. We had started at that time to look at it as something horrible, something that should not be continued.

(14) Harold Agnew was a physicist working on the Manhattan Project. He was interviewed for a BBC television documentary, The Building of the Bomb, in 1965.

I think it was right to drop the bombs because I believe that the dropping of these bombs brought the war to a close much quicker than would have been possible otherwise. I think if people who now debate this question had seen the preparations which we were making for evacuating the wounded, the hospital preparations and everything, anticipating an actual landing, that they would have realised that we actually saved lives: not only our own soldiers' lives, but the lives of the Japanese, because had we been forced to actually attempt to occupy the island I think the death toll would have been tremendous.

(15) Henry Stimson, Secretary of War, letter to President Harry S. Truman (11th September, 1945)

The chief lesson I have learned in a long life is that the only way you can make a man trustworthy is to trust him; and the surest way to make him untrustworthy is to distrust him. If the atomic bomb were merely another, though more devastating, military weapon to be assimilated into our pattern of international relations, it would be one thing. We would then follow the old custom of secrecy and nationalistic military superiority relying on international caution to prescribe the future use of the weapon as we did with gas. But I think the bomb instead constitutes merely a first step in a new control by man over the forces of nature too revolutionary and dangerous to fit into old concepts. My idea of an approach to the Soviets would be a direct proposal after discussion with the British that we would be prepared in effect to enter an agreement with the Russians, the general purpose of which would be to control and limit the use of the atomic bomb as an instrument of war.

(16) Freda Kirchwey, The Nation (18th August, 1945)

The bomb that hurried Russia into Far Eastern war a week ahead of schedule and drove Japan to surrender has accomplished the specific job for which it was created. From the point of view of military strategy, $2,000,000,000 (the cost of the bomb and the cost of nine days of war) was never better spent. The suffering, the wholesale slaughter it entailed, have been outweighed by its spectacular success; Allied leaders can rightly claim that the loss of life on both sides would have been many times greater if the atomic bomb had not been used and Japan had gone on fighting. There is no answer to this argument. The danger is that it will encourage those in power to assume that, once accepted as valid, the argument can be applied equally well in the future. If that assumption should be permitted, the chance of saving civilization - perhaps the world itself - from destruction is a remote one.