From January, 1939, until American troops finally entered Germany and we took into custody a number of the senior German scientists, we faced the definite possibility that Germany would produce a nuclear weapon before we could. For that reason it was absolutely essential for us to remain as fully informed as possible on German progress in this field.
When the Manhattan District was formed, American intelligence efforts on atomic energy matters were carried out separately, as a part of their general activities, by the Army and Navy intelligence agencies (G-2 and ONI), and by the OSS. In addition, a number of other intelligence agencies scattered among the various government departments were gathering scraps and bits of information within the enemy nations that might be useful in adding to the atomic picture.
In the fall of 1943, General Marshall asked me, through Styer, whether there was any reason why I could not take over all foreign intelligence in our area of interest. Apparently, he felt that the existing agencies were not well co-ordinated; and that, as a result, there were many gaps not being covered. Moreover, it was probable, he thought, that these agencies would not always recognize the particular importance to us of some of the information they might receive, since, for security reasons, we had to limit the number of outsiders to whom we needed to explain the kind of information we wanted.
In the course of my conversation with Styer, I was surprised to learn that there was considerably more friction between the various intelligence agencies than I had previously suspected. There seemed to be no alternative to my taking this added responsibility. As was customary, nothing was put in writing. We simply agreed that General Marshall would inform Major General Strong, then Army G-2, of the change and that I would take care of notifying OSS and ONI.
The first step was to discuss the problem personally with Strong, and then through Admiral Purnell, to establish proper contacts with ONI. Immediately thereafter I paid a call on Major General William Donovan, the head of OSS, and at the same time saw his Executive Officer, Colonel G. E. Buxton. Donovan designated Lieutenant Colonel Howard Dix to look out for our interests and to ensure that all atomic information collected by OSS would be forwarded promptly to the Intelligence Section of my office.
I was astounded to learn how thoroughly unsatisfactory the relationships were between G-2 and OSS. As I was leaving at the close of our discussion, Donovan remarked that I was the first general officer who had ever come to see him in his office. He appeared to be quite touched by this and insisted on personally escorting me out of the building and sending me back to my office in his own car, even going so far as to insist on holding the door for me while I got in. Buxton told me afterward that OSS would have supported us fully in any case, but that my call ensured the utmost in special treatment for the MED. I never tried to find out the reasons for the unfortunate relationships that had grown up among the various intelligence agencies, but we always enjoyed splendid co-operation from every one of them.
My experience here was a graphic demonstration of the importance of extending common courtesy to those with whom you expect to conduct important business. There is no substitute for it. Going out of our way to establish initial contacts with other organizations and individuals through calls by senior personnel, instead of by letter or telephone, was common practice in the Manhattan Project.
The new intelligence mission of the MED was clear: We had to learn as soon as we could what the Germans might be able to do if they exerted every possible effort to produce an atomic weapon. Throughout the project, there was universal respect for the quality of German science. This was a feeling I shared wholeheartedly. Our scientific people were acutely conscious that European scientists had discovered the principle of fission, and that our enemies were continually harping on their proposed use of secret weapons. Although this was sometimes hard on our nerves, it did keep us from ever becoming overconfident of the superiority of American-British efforts in the field of nuclear physics. Unless and until we had positive knowledge to the contrary, we had to assume that the most competent German scientists and engineers were working on an atomic program with the full support of their government and with the full capacity of German industry at their disposal. Any other assumption would have been unsound and dangerous.
It made no difference whether we thought, as we did when our own work made us realize the enormous difficulties involved, that they probably would not be successful. The fact is that they did possess the necessary capabilities, particularly if they generally ignored safety considerations; and this I was certain they would do. Our chief danger was that they might come up with relatively simple solutions to the problems we were finding so difficult.
We did not make any appreciable effort during the war to secure information on atomic developments in Japan. First, and most important, there was not even the remotest possibility that Japan had enough uranium or uranium ore to produce the necessary materials for a nuclear weapon. Also the industrial effort that would be required far exceeded what Japan was capable of. Then, too, discussions with our atomic physicists at Berkeley, who knew the leading Japanese atomic physicists personally, led us to the conclusion that their qualified people were altogether too few in number for them to produce an effective weapon in the foreseeable future. Finally, it would have been extremely difficult for us to secure and to get out of Japan any information of the type we needed. I hoped that if any sizable program was started, we would get wind of it from one of the various intelligence-collecting agencies with which we maintained liaison. In that event, we would have immediately done everything we could to interfere with their operations.
Positive support for our reasoning that the Germans were vitally interested in atomic energy had come from Norway, where before the war, in the town of Rjukan, about seventy-five miles west of Oslo, the Norwegians had constructed a complex of hydroelectric and electrochemical plants. When the Nazis occupied the country in 1940, they had required the operators of the Rjukan works to enter into contracts to produce heavy water which was to be shipped to Berlin for experimental use in the development of atomic energy. In September of 1942 we had estimated that approximately 120 kilograms of heavy water were being delivered to the Nazis each month under the terms of this contract.
At my instigation, Strong, with the approval of General H. H. Arnold and Major General T. T. Handy,1 had brought this matter to the personal attention of General Eisenhower, and suggested that the Rjukan plants be either bombed or sabotaged.
The first attempt to put these works out of commission involved the use of guerrilla forces. Some five months after my request, three Norwegians, especially trained in sabotage techniques, and wearing British uniforms, parachuted into Norway, where they were met by local guerrillas. After nearly a week of hard cross-country skiing, they arrived at Rjukan and attacked the factories there on February 27, 1943.
The first reports on this action were most encouraging. A news dispatch from Oslo, which was relayed to Stockholm, stated that damage was “not extensive except at the place where the attempt was made and there the devastation was total.” Subsequent reports from Sweden were even more encouraging, calling this “one of the most important and successful undertakings the Allied saboteurs have carried out as yet during the war.”
These same Swedish newspapers caused me some headaches when they went on to speculate at considerable length about the importance of heavy water, pointing out that “many scientists have pinned their hopes of producing the ‘secret weapon’ upon heavy water, namely an explosive of hitherto unheard-of-violence.” These items were picked up by the London papers and finally, on April 4, 1943, New York readers were greeted by such headlines as “Nazi ‘Heavy Water’ Looms as Weapon.” Immediately, Dr. Harold Urey, who had discovered heavy water, was deluged with calls from reporters wanting more information. He neatly sidestepped all such inquiries with the statement that “So far as I know, heavy water’s uses are confined solely to experimental biology. I have never heard of an industrial application for heavy water, and know of no way it can be used for explosives.”
Meanwhile, the British were hard at work assessing the damage done to the Rjukan works in the February raid. Their first estimates indicated that heavy-water production had been set back by about two years. We had different information, but our suspicions were not confirmed until we learned definitely that the plant had resumed partial operations in April. Yet doubt can be contagious and, under our gentle prodding, Sir John Dill soon felt himself compelled to inform General Marshall that a more realistic appraisal of the damage indicated that the plant could be completely restored in about twelve months. After some discussion of launching another commando raid—a full-scale one this time—General Marshall, at my behest, proposed to Sir John Dill that, instead, the plants be made a first priority bombing objective. This proposal led ultimately to a massive air attack on Rjukan in November of 1943. Although this mission in itself was not particularly destructive, it apparently led the Germans to believe that more attacks would follow. This belief, together with the problem of constant sabotage by workers in the plants, and probably a lack of appreciation at high government levels of the possible value of the product, caused the Nazis to give up their attempts to repair the damage done by the saboteurs in February. All apparatus, catalyzers and concentrates used in the production of heavy water were ordered shipped to Berlin. Norwegian guerrillas interfered with every step of the transfer, successfully destroying much valuable equipment and even going so far as to sink the ferry which carried a large part of the heavy water.
Even before the MED took over the responsibility for atomic intelligence in the fall of 1943, I had had a number of discussions with Strong about the desirability of exploiting sources of information that would become available to us as the American Fifth Army advanced up the Italian peninsula. I thought that we might be able to learn something of German progress in the field of atomic energy, and thus estimate more realistically how much time we had left to complete our own project; possibly we might obtain some useful technical information. In this I had the concurrence and hearty support of Bush.
Some staff officers in G-2 and certain scientists in the OSRD were pursuing similar approaches to the solution of their own particular problems. The result of their efforts and mine was a decision to make an organized attempt to tap Italian sources of scientific and technical information.
After consultation with Bush and with me, and with our wholehearted agreement, Strong, in September, 1943, put the proposal to General Marshall. His memorandum of that date said, in part:
While the major portion of the enemy’s secret scientific developments is being conducted in Germany, it is very likely that much valuable information can be obtained thereon by interviewing prominent Italian scientists in Italy. . . . The scope of inquiry should cover all principal scientific military developments and the investigations should be conducted in a manner to gain knowledge of enemy progress without disclosing our interest in any particular field. The personnel who undertake this work must be scientifically qualified in every respect. ... It is proposed to send at the proper time to allied occupied Italy a small group of civilian scientists assisted by the necessary military personnel to conduct these investigations. Scientific personnel will be selected by Brigadier General L. R. Groves with the approval of Doctor Bush and military personnel will be assigned by the Assistant Chief of Staff, G-2, from personnel available to him. . . .
He went on to indicate that “This group would form the nucleus for similar activity in other enemy and enemy occupied countries when circumstances permit.”
Thus G-2 and I, and the Navy, which later asked to be represented on the mission, became partners in obtaining intelligence from an active theater overseas.
The Manhattan Project always carefully avoided drawing undue attention to its work and to its people. Code names for our projects were deliberately innocuous. Imagine my horror, then, when I learned that G-2 had given the scientific intelligence mission to Italy the name of “Alsos,” which one of my more scholarly colleagues promptly informed me was the Greek word for “groves.”2 My first inclination was to have the mission renamed, but I decided that to change it now would only draw attention to it.
Alsos differed in many respects from other intelligence units then existing in either the American or British forces. Its purpose was to supplement, but not to overlap or duplicate, the other agencies, and we emphasized always that our people should make the utmost use of the resources of the already established units. This practice enabled us to eliminate surplus personnel and administrative confusion, and proved to be especially effective during the preliminary planning phases of selecting intelligence targets. It also secured the wholehearted co-operation from G-2 organizations in the field.
Though Strong’s memorandum made no mention of atomic energy, everyone concerned in the higher levels recognized that the mission’s primary purpose was to obtain intelligence of atomic developments in Italy and Germany. Nevertheless it was logical to expect that, in the course of its work, the mission would also come upon data about other enemy projects; accordingly, it was directed to exploit to the fullest sources in a number of fields of technical interest. For this reason, after discussions with Bush, I recommended that the mission report directly to Strong, who would relay its findings to the appropriate agency. This was the procedure followed throughout the mission’s existence.3 My purpose in this was not altogether altruistic; for my principal concern, I admit, was to draw attention away from the mission’s interest in atomic matters. So strongly did I feel about this that in November, 1944, I wrote to my personal representative with the mission:
The impression has been created that ALSOS has been acting solely for us. This is injuring both ALSOS and ourselves. ALSOS has a definite mission in many fields, one of which concerns us, Any idea on the part of those in authority that ALSOS is completely monopolized for our purposes must be corrected.
The original detachment forming the mission was to consist of thirteen military personnel, including interpreters, and not more than six scientists, either civilian or military. Its make-up was considerably different from that of other intelligence units. It included people who were capable of extracting through interrogation and observation detailed scientific information on atomic energy. It also contained people who were generally familiar with the research programs and interests of both the United States and Great Britain and, insofar as possible, of our enemies. The members of the mission had to have a general knowledge of enemy equipment and they had to be prepared to seek out not only military laboratories and technical personnel, but civilian scientists, technicians and facilities as well.
The objectives of Alsos in Italy were: “To obtain advance information regarding scientific developments in progress in enemy research and development establishments which are directed towards new weapons of war or new tactics . . . and to secure all important persons, laboratories, and scientific information immediately upon their becoming available to our own forces before their dispersal or destruction.” Its efforts would enable us to select bomber targets, develop countermeasures against new weapons, organize counterpropaganda, plan our strategy and direct our own war research projects.
The mission was to conduct investigations in occupied Italy only, and was to advance with, or closely behind, our military forces to Rome, proceeding further north whenever it felt that important targets could be found. Unfortunately, our plans were based on the then-expected rate of advance to Rome. This rate was not achieved and, consequently, there was a considerable period of time during which the mission was unable to operate with full effectiveness.
Alsos was commanded from the beginning by Lieutenant Colonel Boris T. Pash. I had first met Pash in San Francisco, where he was working on a security matter involving the project at the time when such affairs were still handled in G-2. His thorough competence and great drive had made a lasting impression upon me. His unit originally consisted of an executive officer, four interpreters, four CIC agents and four scientists, Major William Allis (War Department), Lieutenant Commander Bruce S. Old (Navy Department), and Dr. James B. Fisk and Dr. John R. Johnson (both of the OSRD).
From information available to us in November, 1943, we considered it desirable to begin scientific investigation in Italy at the very earliest opportunity. Discussions with Vice Admiral Minissini of the Italian Navy had given us no grounds to believe that the Italians were working on an atomic weapon; nevertheless, we had evidence that all possible information on this subject was not reaching the MED through our established channels. On November 10, therefore, I urged G-2 to request the theater commander to authorize Alsos to conduct investigations immediately in that part of Italy which was then under American control.
The mission assembled in Algiers on December 14. After visiting the several commanders in whose areas they would be operating, the group departed for Naples, where they established contact with the Fifth Army Intelligence Section and the Italian Civil Government. They spent the next month and a half interviewing Italians at Naples, Taranto and Brindisi who might know something about the research efforts in Germany and unoccupied Italy. It soon became apparent that the most worth-while sources of Italian information were in Rome. Two plans were drawn up to exploit these sources. One would attach the Alsos mission to the troops of the Fifth Army, to enter Rome immediately after the city fell; the other would secure and bring back certain important scientists from Rome and northern Italy before Rome was captured. Neither of these plans could be carried out immediately, however; and since the Allied progress northward was slow and efforts to obtain information from Italians behind the enemy lines were generally unsuccessful, the mission gradually became inactive. By March 3, 1944, all its members had returned to the United States.
In spite of their disappointment over the inability to enter Rome, this first Alsos mission was most successful. Indeed, its accomplishments so far exceeded what we had considered possible that its conclusions were generally discounted, principally because its findings were essentially negative. While it discovered several items of immediate interest to both the Army and the Navy, any one of which would have justified its existence, the best that it could arrive at in our particular field was: “Almost all the evidence gained points toward no particular experimental activity by the Germans on explosives based on nuclear energy.”
On the basis of this report, I felt justified in concluding that the German atomic energy effort was not so intensive as ours. Alsos’ confirmation of the fact that control of the Germans’ work still remained in the hands of research scientists indicated that they probably had not yet got to the point we had reached by the summer of 1942, when primary responsibility for our program passed from the OSRD to the Army.
However, we could not be absolutely sure that we were not being misled by the general lack of positive information. In its report at the close of its activities in Italy, the mission recommended that “steps be taken to obtain scientific intelligence in new theatres of military operation as they are developed,” and that “careful consideration be given to the potential value of conducting scientific intelligence operations in the wake of the anticipated invasion of Western Europe.” I concurred in these recommendations, as did Major General Clayton L. Bissell, who by then had succeeded Strong as G-2.
In December, 1943, just about the time the Alsos group was landing in Italy, I had sent one of my officers, Major R. R. Furman, to England to confer with officials in the British Government about the possibility of establishing a Manhattan liaison office in London and engaging in a joint Anglo-American intelligence effort. The idea was well received by the British and in January, 1944, we selected Captain Horace K. Calvert4 to head the liaison office.
He was not picked for this important assignment because of his technical background, for he was an oilman-lawyer in peacetime. However, since he had had a thorough training in intelligence procedures and an extensive background in the project, we felt that he would be well qualified to recognize any danger spots in the German picture. Before he left, I gave him brief and quite general instructions. He was to gather all possible information on the various atomic energy efforts under way in Europe, particularly those being carried on by the Germans; to make use as far as possible of existing American and British channels; to keep his intelligence estimate up to date at all times and to report to us in Washington everything that he considered to be of importance. He was also expected to establish close and friendly relations with the Englishmen and Americans with whom we might have to deal from time to time, both in London and, as the situation developed, on the Continent.
We provided him with a letter of introduction from General Strong, to Colonel George B. Conrad, G-2 of ETOUSA.5 Immediately after arriving in London, he reported to Conrad to present his credentials. I had always advised our officers to avoid any unnecessary demonstration of the usual military formalities whenever they felt that it might irritate our civilian scientists. Apparently Calvert had been well indoctrinated, for, somewhat flustered at reporting to a senior officer, instead of saluting, he just put out his hand and said, “Good morning. I am Major Calvert.” Even now, some eighteen years later, he has not forgotten the horror that swept over him when he realized that he had failed to salute. He knew that Conrad and I had been roommates at West Point, and this only added to his embarrassment. Fortunately, Conrad accepted Calvert’s greeting in the spirit in which it was offered and set him at ease by shaking hands and showing him to a chair. Calvert then told him of the basic purpose of the MED and of his own mission. Out of their conversation came arrangements for Calvert to have a desk in Colonel Conrad’s office where he could go over all the raw intelligence data as they came through.
At the start, it was impossible to set up any criteria for the kind of information in which we might be interested; later, as Calvert became familiar with the various types of intelligence, he was able to eliminate certain classes of data as being of no interest.
After establishing himself in intelligence circles, Calvert called on Mr. Winant, our Ambassador to England, to whom he gave such general information as he felt to be necessary and appropriate. Again, he was furnished with a desk and the utmost support. Soon he was given the title of Assistant Military Attache.
Calvert acquired a third desk in the British Atomic Energy Office, which carried the cover name of Tube Alloys. Here he maintained close liaison with the head of the office, Michael Perrin; his assistant, David Gattiker; and Lieutenant Commander Eric Welsh (of the British Intelligence); all of whom had a lively sympathy for his efforts.
Messages to and from Calvert passed through the American Embassy in London and the War Department. Cable messages were always sent in top secret code and, as an extra precaution, many of the key words were previously coded into the names of states, cities or other common words. For example, “New York” might be used for “uranium,” “Indiana” for “plutonium,” “Nevada” for “British Intelligence,” and so on, the code being changed from time to time.
After a short time, Calvert was joined by another officer, Captain George C. Davis, three WAC’s and two counterintelligence agents. Furman, in my office, was Calvert’s Washington contact man. I used Furman primarily for special projects such as this one. His actions were always prompt and to the point.
In making his initial appraisal of the German atomic picture, Calvert knew it would take a combination of three requisite factors to make a bomb. Those were: (1) a sufficient number of top nuclear scientists and technical assistants; (2) the basic fuel for a bomb—uranium, and possibly thorium, probably combined with uranium; and (3) laboratories to develop it and industrial means to make it.
He started working on the fuel problem first, for we were sure of Germany’s scientific and industrial ability to do the job. Thorium seemed out of the question, since it is mined chiefly in Brazil and India and, because of embargoes, Germany had been unable to import any since the war began, and had had only insignificant stocks on hand before the war. The basic fuel was thought to be uranium. Considering our own firsthand knowledge of the enormous industrial effort required to produce U-235, we were confident that we would have seen evidences of any such program had one existed. It seemed more likely that they would use plutonium. That they had enough to launch an atomic program seemed to be within the realm of possibility, for we knew there had been a large stockpile of refined uranium ore at Oolen, Belgium, a few miles outside Brussels, which originally had been the property of Union Miniere.
The only other possible supply of uranium was the mines at Joachimsthal, Czechoslovakia, which was not a particularly significant source. Most of this ore was shipped to a uranium plant outside Berlin, the Auer-Gesellschaft. British Intelligence kept in touch with the activities of these mines, and in July, 1944, Calvert’s group started periodic aerial surveillance over the entire mining area, studying the pictures in detail for new shafts and aboveground activity. Tailing piles from each mine were microscopically measured from one reconnaissance to the next. By knowing the general grade of the ore and measuring the piles, we could determine with some degree of accuracy the mine’s daily production. There were no signs of extraordinary activity.
It would have been imperative for Hitler to enlist the aid of all his top scientists. Allied Intelligence had established that many of them were working on the “V” weapon; particularly at Peenemiinde, but to our knowledge no nuclear physicists had been reported there. Calvert started a search for some fifty German nuclear scientists. He knew that there must be many young scientists who had come up since Hitler’s rise to power of whom we had no knowledge; however, if we could locate a few of the top people, they should lead us to the rest. All the present and back issues of the German physics journals were scrutinized. Foreign-born nuclear scientists in the United States, like Enrico Fermi, O. R. Frisch and Niels Bohr, as well as anti-Nazi professors and scientists in Switzerland, Sweden and other neutral countries, were questioned in detail to obtain any past or present information they might have on the whereabouts of the German scientists. The names of all German scientists were placed on watch lists with American and British intelligence agencies which were daily scanning German newspapers that had been smuggled out. Before long we had recent addresses for a majority of the scientists in whom we were interested.
The third main category of pre-D-Day investigation, laboratories and industrial plants, was studied in much the same way. Lists were compiled of all of the precious metal refineries, the physics laboratories, the handlers of uranium and thorium, manufacturers of centrifugal and reciprocating pumps, power plants and other such installations as were known to exist in the Axis countries. These were placed on a master list from which they were not removed until we had positive information that they were not engaged in, or supplying, an atomic program. All plants where work of an unknown nature was being conducted were checked through aerial reconnaissance, the underground, OSS and all the numerous intelligence agencies.
By hard work and constant effort, Calvert was ready by the time the second Alsos mission reached Europe on the heels of the invading armies with a good list of the first intelligence targets, dossiers on all the top German scientists, where they worked and where they lived, the location of the laboratories, workshops and storage points of interest.
1 Head of Operations Division, War Department, General Staff.
2 Actually it is “grove.”
3 Reports to me on atomic matters always came in sealed envelopes through G-2, without being opened.
4 Then head of MED security activities; previously with the Investigations Branch of Army G-2.
5 European Theater of Operation, U.S.A.