The CHAIRMAN. Are you familiar with the explosions that have taken place on land already?

Dr. SAWYER. I did not observe them, but I am familiar with the data which were obtained from them.

The CHAIRMAN. What do you think will be the benefit to science and to the Army and Navy as a result of the holding of these tests?

Dr. SAWYER. I should say, to the Army and Navy, these tests are indispensable if we are to prepare to defend ourselves against possible attack from atomic bombs in the future. I consider that to be the function of the Army and Navy, or the principal function of the Army and Navy, in peacetime-to consider the attacks which they may have

to meet.

It seems to me that it is impossible to do that unless they know what the effect will be of such detonations on Army and Navy equipment, including ships.

The CHAIRMAN. From the scientific standpoint, what do you say, aside from the Army and the Navy?

Dr. SAWYER. You mean, from the standpoint of pure science?

The CHAIRMAN. Well, what benefit will there be to scientists and to scientific research?

Dr. SAWYER. As to direct additions to pure science, they will not be large. This is not intended as a pure scientific experiment, to advance our knowledge about the atomic bomb or about nuclear fission.

It will, however, advance the knowledge of science in several ways. We expect, as part of the work, to get the information which the Navy needs on oceanographic work, the effects on plant and fish life, animal life, which will be of scientific value.

We also expect to get additional information which has not been obtained from the previous tests as to the phenomena associated with a blast of this size and extent.

We consider that it is not possible to scale out from smaller explosions with sufficient accuracy to be certain about the effects to be expected in a detonation of this magnitude.

The CHAIRMAN. Well, have you not gleaned some data as to the effects on human life and animal life from the other experimentation, from the actual explosions of the atomic bombs during the war?

Dr. SAWYER. Yes; some information has been collected on the effects that have been observed at Nagasaki and Hiroshima. Of course, that information is of value; and it cannot be reproduced in this test.

On the other hand, that is all hearsay observation. We have to take statements of people as to where they were, what they were doing at the time of the explosion.

Furthermore, we shall get more information from this test as to the radioactivity associated with the bomb, measured information. The CHAIRMAN. Which would amplify the information already had?

Dr. SAWYER. Yes, sir.

The CHAIRMAN. Any questions?

Senator SALTONSTALL. Yes, Mr. Chairman.

The CHAIRMAN. The Senator from Massachusetts.

Senator SALTONSTALL. Aren't you a little overmodest in your statement of what pure science will get from this test, if your job is well done? You say you are working for the Navy, so you are very careful to say that you are just doing it for the Navy.

However, if you do your job well, there is certainly going to be some fundamental information obtained on radioactivity and other effects of the explosion, and so on?

Dr. SAWYER. We will get a lot of oceanographic information, a great deal of information on radioactivity and illumination. Such studies will certainly be of scientific value.

I only wish to say that this is not intended primarily as a test of atomic fission, to increase our information on that.

Senator SALTONSTALL. But the scientists certainly hope that you do your job well, don't they?

Dr. SAWYER. Yes, I anticipate they do; yes, sir.

The CHAIRMAN. Are there any other scientists associated with you? Dr. SAWYER. Yes, sir; of course. We have a large staff of scientists to carry out these measurements.

Most of them are civilian scientists, although some of them are military scientists and Reserve officers, who are in uniform.

The number of personnel which will carry out the measurements that I supervise is about 1,000.

Of that 1,000, perhaps 400 or 500 may be carrying out routine observations, such as photography or monitoring the radioactive effects.

Some 300 or 400 of these could certainly be called trained scientific personnel, and they come from a wide variety of places, from the Army and the Navy, from laboratories and bureaus, from contract employees of the Army and Navy, university contractors.

The CHAIRMAN. Any other questions?

Seantor EASTLAND. How far do you estimate the wave will travel? Dr. SAWYER. The wave produced by the explosion?

Senator EASTLAND. Yes, the wave created by the explosion. How far do you estimate that wave will travel?

Dr. SAWYER. From the first explosion which, as you know, will be in the air, or above the water, we expect rather small waves, of course. We have no information on that, of course, except an estimate, but we believe those waves will certainly not get outside the lagoon.

From the second explosion, the second shot, which will be on the surface or under water, the waves will be much larger. However, we still think that by the time they reach the reef of the lagoon, they probably will not be more than 5 or 10 feet high. There will be very little wave observed outside the lagoon, we feel sure.

The CHAIRMAN. Well, couldn't that effect on the surface of the ocean, the creation of these waves, be discovered or ascertained by dropping a bomb without any ships at all there?

Dr. SAWYER. Yes, sir; the waves could be and they certainly could be measured without the presence of ships.

Of course, the fundamental importance to us of this test, or these tests, I should say, is the effect of the wave on ship motion; the effect of the shock in the water and in the air on the ships themselves and on component parts and equipment.

The CHAIRMAN. I should think it might be possible to estimate that, to ascertain what would be the disturbance on the surface of the sea. Dr. SAWYER. Yes, sir; you could estimate the disturbances; but the effect on ships, I think, you could not estimate.

I would like to make this point, that we have no experience on the effect of shock, either in the air or under water, of this weapon.

Here we will apply to the whole area of the battleship at one time a tremendous shock.

No explosions which ships have endured in wartime is comparable to an explosion of this kind from the atomic bomb.

No ship constructor can estimate what the effect of, say, applying a ton per square inch on the whole surface of the ship at one time will be, from any under-water mine or torpedo explosion of which we have had any experience.

It may be that the effect will not be what we expect or predict from our previous knowledge.

Senator EASTLAND. As I understand it, from what I have heard about the exploding of the atomic bomb, an explosion beneath the surface would be much more powerful than the effect of the bomb when it is exploded on the surface of the water or in the air. Is that an accurate statement?

Dr. SAWYER. Yes, sir.

Senator EASTLAND. Do you have any information on whether or not a bomb dropped or exploded beneath the surface of the open sea would create a tidal wave?

Dr. SAWYER. No, sir; it would not create a tidal wave. It would create local waves, wave disturbances, but of a strictly limited nature. Senator ROBERTSON. Dr. Sawyer, did I understand you to say that you have about 1,000 assistants or observers or helpers in the scientific end of this test?

Dr. SAWYER. Yes, sir.

Senator ROBERTSON. Are those confined to citizens of the United States?

Dr. SAWYER. With two or three exceptions.

Senator ROBERTSON. Would you like to mention those exceptions? Dr. SAWYER. Admiral Blandy, would you wish to reply to that? Admiral BLANDY. British scientists formerly associated with the Manhattan project.

Dr. SAWYER. There are a few British scientists, five or six, who have been associated with the Manhattan district during the war, and who will take part in this test.

Senator ROBERTSON. Those are the only ones?

Dr. SAWYER. Yes, sir.

Senator EASTLAND. You have checked on the background of the 1,000 employees?

Dr. SAWYER. Yes, sir; every single one of them will have an individual investigation.

Senator EASTLAND. By what department?

Dr. SAWYER. The task force has a security and intelligence organization which initiates these investigations. For the people who will have more immediate contact with the bomb, those people will have special investigations made by the Manhattan District, also.

Relatively few of these people will come in contact with the bomb at all.

Senator GERRY. Doctor, you think, don't you, that probably, in shallow water, the bomb will not be as effective as it will be in deep water, I mean insofar as damage to ships?

Dr. SAWYER. It will be more effective in deep water.

Senator GERRY. More effective in deep water; and you want to find how deep that has to be, don't you, to get that measurement?

Dr. SAWYER. We can make some computations.

Senator GERRY. This test will help you?

Dr. SAWYER. Yes; the real reason for carrying out the under-water tests is to get information which we cannot obtain by calculation or from the tests which have been made over land previously.

The CHAIRMAN. Doctor, this may be an amateurish question.
Dr. SAWYER. Yes, sir, that is right.

The CHAIRMAN. Is it possible for different types to be discovered or invented that will have more power or will result in more damage and more disturbance and more losses than the bomb that we may use?

Dr. SAWYER. Sir, I am afraid that I couldn't answer that question in detail. I can say that I consider such things are possible; that testimony has been given by General Groves in that connection, and by others before the hearings on atomic energy.

The CHAIRMAN. You plan to use a certain type of atomic bomb? Dr. SAWYER. The bomb that will be used will be the size and type used at Nagasaki.

The CHAIRMAN. Suppose a larger one or possibly a more powerful one is used by one of our prospective future enemies, do you suppose they could predict the results by what you may discover from this size and type of bomb from these tests? Could you make such measure

ments?

Dr. SAWYER. We could certainly extrapolate, from the results of the testing of this bomb, the expected results to be obtained from bombs of the same order of magnitude or 5 or 10 times greater.

If a bomb of 1,000 times this power should be made, then we cannot, perhaps, extrapolate that effect, any more than we can extrapolate the effect of this one, from calculations taken from the explosion of a 1,000-pound bomb.

The CHAIRMAN. Is it possible to make a bomb of greater power than the one you contemplate using?

Dr. SAWYER. Is it possible!

The CHAIRMAN. Yes, or probable; or is this the maximum destructive bomb that is now known or can be conceived of?

Dr. SAWYER. Well, Senator, I might answer that by saying it is certainly possible to conceive of more destructive bombs. This bomb is the bomb we have at the present time.

Certainly I am not in a position to make any statements of what we may have 5 or 10 years from now, whether it will be more effective or less effective, assuming that we go ahead with the development of the bomb.

Senator ROBERTSON. You probably have seen in the newspapers, Doctor, or in the magazines, or both, that many people are concerned about the possible effects of this underwater explosion, as to developing explosive qualities, developing something not confined to the bombs -you know what I mean, reactions.

Dr. SAWYER. You mean, Senator, that we may burn up the ocean? Senator ROBERTSON. Yes. I don't say exactly burn up the ocean; but there have been some very extraordinary suggestions proposed. Would you like to make a statement on those?

Dr. SAWYER. Yes, sir. I consider that those statements are irresponsible. This is a question we have studied with great care.

I can assure you there is no possibility of such reactions. We will not burn up the ocean; we will not set off a volcano; and we will not burn up the atmosphere.

I consider that our experts, who worked on this question, have had the information and the ability to answer the question correctly.

I have no respect for those statements which I have seen in the press. Senator ROBERTSON. Well, Doctor, I am sure your answer is very reassuring or should be reassuring to many people.

Dr. SAWYER. Certainly, sir, you wouldn't expect us to go out and do this thing if there was any possibility of that happening?

Senator ROBERTSON. I am not one of those that suggests those possibilities.

Dr. SAWYER. Well, sir, I am going myself; I am going as a volunteer, but not as a guinea pig. [Laughter.]

The CHAIRMAN. Any other questions?

(No response.)

The CHAIRMAN. Dr. Compton, will you come forward, please?

STATEMENT OF DR. KARL T. COMPTON, PRESIDENT, MASSACHUSETTS INSTITUTE OF TECHNOLOGY, MEMBER OF PRESIDENT'S EVALUATION COMMITTEE, AND MEMBER OF JOINT CHIEFS OF STAFF EVALUATION BOARD

The CHAIRMAN. Gentlemen, I present to you Dr. Karl T. Compton, the president of the Massachusetts Institute of Technology, member of the President's Evaluation Committee, and member of Joint Chiefs of Staff Evaluation Board.

Doctor, first of all, I want to say that we appreciate greatly your coming here in response to our invitation.

I have observed in the press that you had given out a statement indicating the importance of holding this test and the value of it. I would like to have you elaborate to the committee your views along that line, Doctor, if you will.

Dr. COMPTON. Senator Walsh and gentlemen of the committee, I do consider, although I am a member of these evaluation boards, I am convinced that the tests ought to be made, and I say that without any compulsion due to my membership on these boards.

Perhaps I can illustrate that by saying that as long ago as last September, when I was in Tokyo, I urged on some of the officers there that tests be made while there was an opportunity for making the

tests.

My reason was this: That unless these tests are made there would be, it seems to me, endless argument and discussion without coming to any certain conclusion with regard to what would be the effect of atomic bombs on naval ships or what ought to be done to protect the ships, and questions of that sort; it seems to me that the only way to avoid endless discussion and uncertainty was to carry out the tests and get the facts.

I remember on the Baruch rubber committee, Mr. Baruch used to emphasize over and over again when questions came up, the same thing. He said, "Let us not argue or draw our conclusions until we get the facts." That, I take it, is the purpose for these tests.