Pioneers in Science and Technology Series: Philip Abelson

              
PIONEERS IN SCIENCE AND TECHNOLOGY SERIES

ORAL HISTORY OF DR. PHIL ABELSON
Interviewed by Clarence Larson
Filmed by Jane Larson
November 20, 1983
Transcribed by Jordan Reed
 
DR. ABELSON: I, first as a scientist [inaudible] career really related to the fact that I got interested in chemistry during the undergraduate years in college. I then was fortunate in having a teaching assistantship in physics. I have a master’s degree in physics from Washington State. Then I was also fortunate in obtaining an assistantship at Berkeley. I was the only out of state student to obtain such a fellowship that year. That was 1935 and Ernest Lawrence was already developed a cyclotron, but it was still in a state of development. He had also assembled in the radiation laboratory there about 15 or 20 top bright people. People like Louie Alvarez and Ed McMillian. So there was a cyclotron and it was the world’s best source of radiation at that time, particularly of neutrons and the whole world of the periodic table was available to us to explore and see what would happen when various elements were irradiated either by neutron alpha particles or neutrons.
MR. LARSON: What year was artificial radioactivity discovered so that…
DR. ABELSON: 1932 was the first year of that, but the people that were working on artificial radioactivity had very weak sources to deal with and incidentally one of the groups that were working using such sources was the Fermi group in Rome. And along about in 1935, the fall of 1935 they announced that they had found transuranic elements. Not long after, Ernest Lawrence approached me and said that was a very interesting paper. There should be some alpha particles related to the elements and so he encouraged me to attempt to irradiate uranium and get some products which we tested for alpha particles. Well we did it and didn’t find the, such alpha particles, but the equipment at that time was pretty insensitive. 
MR. LARSON: What type of detectors did you use?
DR. ABELSON: Well at that time it was simply a linear amplifier. For our studies of the electron radioactivity we used a so-called Lawrenson Electroscope, which Lawrenson was going to sell for $35. 
MR. LARSON: Yes, I can remember that very well. I started some elementary experimentation about 1937. Lawrence gave me some of the bi-product targets that had some radioactivity and I used the Lawrenson Electroscope. I got one of the very expensive Lawrenson Electroscopes at that time also. I never was able to afford a Geiger counter. 
DR. ABELSON: Well and then they were somewhat complicated too and cyclotrons didn’t always work. Well I continued to pursue the interest in uranium and its products in neutron irradiation. I of course determined that something very complex was happening because there were many, many examples of radioactivity associated with the radiation. One could irradiate for a short period and run to the electroscope and there would be a decay curve that continuously bent over. No matter how you did it, it was obvious that there was a family of radioactivity that added together to make such a curve. Well I of course also tried various chemical separations. In good measure was influenced by the authority of the Italian group and they had come to the belief that a transuranic element should relate to the periodic table and out of that element 93 should be similar to Tungsten, which is an element below it. So they used precipitation, a sulfide precipitation and the sulfide precipitation brought down some radioactivity. Well, so I worked along on this, beating my brains out, and worked all nights on it and the more I worked the more complex it seemed. Finally, in about 1938, I did make a Geiger counter and it was a Geiger counter that had ethyl bromide in it so it could detect x-rays. Then I discovered that sulfide precipitation, the radioactivity associated with it had an x-ray that showed up in the ethyl bromide Geiger counter. So I decided that what I must do was to build a bent crystal spectrometer to identify exactly what the wavelength of that line was that were associated with the transuranic, in order to predict what element could be discovered.  So the bent crystal spectrometer and the associated photographic film aren’t the most sensitive way of detection. I decided that I had to get more uranium because the more uranium there was to irradiate, the more activity could be isolated. About that time, my mother sent down a check for a new suit for me also at that time, Lawrence was in one of those periods where no funds were available. So I took the suit money and went over to San Francisco and bought all the uranium that the suit money could buy and hauled it back. Well the uranium I was going to get was designed for a ceramic application which was terribly dirty. It had holistic acid in it, [inaudible] but in due course I got the uranium cleaned up and I made an irradiation and I managed to get on the cyclotron for about 2 days running including running all night to make this substance. Then I got it finally isolated and put it on the spectrometer. 
MR. LARSON: What radiation was it? Was this the deuteron radiation or neutrons?
DR. ABELSON: This was neutrons.
MR. LARSON: Neutrons.
DR. ABELSON: Neutrons on uranium. Well, just about exactly this time, I was running a further chore. While I was running my isolations, I had the further duties on the cyclotron to make chasers for Lawrence, while I was running the cyclotron in came Louie Alvarez [inaudible]. He had been in the barber shop getting a haircut and had read the newspaper and had learned that Niels Bohr had told a Washington gathering that they had found fission. So Louie jumped out of the barber chair and came running to the laboratory. And of course when he told me that I was terribly shocked because here I was practically in my grasp and I was [inaudible].
MR. LARSON: Apparently there were a number of others who didn’t realize there was a possibility of that.
DR. ABELSON: All the top scientists within a day or two were all able then to confirm the existence of fission by a variety of schemes. Of course I immediately I proceeded to likewise confirm and as it so happened I used the characteristic x-rays and found that it was an iodine x-ray and that they would show a uniquely iodine x-ray. Well, in the next couple of months I identified, oh, a dozen or more fission products, antimony, tellurium, iodine, and xenon. That work became my Ph.D. thesis. Incidentally, one of the products, iodine 131, has been much used.
MR. LARSON: Oh yes. Of course that has a very high yield in fission. So that’s very interesting. 
DR. ABELSON: Well, then that summer, I was invited to come back to Washington to join the group at the Department of Terrestrial Magnetism at the Carnegie Institution. They were set to build a 60 inch cyclotron similar to the one that Lawrence had previously built at Berkeley. So they asked me to join them. That December, about December or January, I was reading in the Physical Review, Segre had been attempting to study further the products of uranium by neutron and he had made some rare earth, co-precipitated some of the radioactivity with rare earth precipitates. So his paper spoke of this and I thought, “Uh-oh, there is something wrong here.” And I’ll bet that instead of the transuranic being a relative of tungsten, I bet that we have a new rare earth series following [inaudible] uranium.
MR. LARSON: Well that is some fascinating conductive reasoning there. 
DR. ABELSON: Well, it was in part from the experience that I had had with the radioactivity. So I set about trying, we had a Van de Graaff generator there at the Carnegie and we made a number of the irradiations and I could see that, yes, of course indeed there was radioactivity on a rare earth-like substance, but there was a problem in proving uniquely that this was a transuranic and not a rare earth. So I thought about these things and studied the chemistry of the rare earths and along about the first of May, I came to the conclusion that a way of getting at it was the fact that when you start with lanthanum, valence 3 by the use of strong oxidizing agents you can convert to cerium which is next to lanthanum, you can convert the cerium to covalence 4. So I thought well maybe that kind of chemistry would be revealing. About that time, I had an occasion to go out to Berkeley and I found that Ed McMillian was struggling also with the question of the possible transuranic. He had developed a nice system in which he irradiated a thin film of uranium oxide. Now the honest to goodness fission product would, at the time they were formed, would have a velocity that would carry them out of the film and a truly transuranic substance would stay in the film. So, he had had evidence that in the film was probably something that was transuranic, and so I came out and I told him my, what I had been up to and the possible chemical identification. So we joined forces and I applied the chemistry there and of course there was the advantage that the radioactivity that was in that thin film was relatively free of all the other mess of fission products. There was still some, but it was quite different from the distribution of [inaudible]. It was quite different from the standard fission product. You know, within a day I had found that I could isolate a nice, clean 2.4 hour radioactivity and it had all the earmarks of being a transuranic and being neptunium. And then within another day what I did was set up a situation in which I isolated, I irradiated the uranium but then isolated the uranium free of fission products, then observed the growth of the 2.4 hour product from the uranium. That’s the real clincher to show that one substance was growing from another. 
MR. LARSON: Well, see it was a combination then of the thin film technique plus then the recognition, you have a different chemistry there that was, enabled you to really come up with this.
DR. ABELSON: Yes, it was that combination. Within 5 days, this element was identified, the paper was written and dispatched, describing it. 
MR. LARSON: Now, that was neptunium 239, wasn’t it?
DR. ABELSON: This was neptunium.
MR. LARSON: 239, with a half-life of 2 point…
DR. ABELSON: 2.4 hours. 
MR. LARSON: 2.4 hours.
DR. ABELSON: And we, at that time, looked for alpha particles from the decayed product, but the 2.4 hour neptunium decays into plutonium for about 10,000 year half-lives. There were just weren’t enough alpha particles to find it. We looked for them.
MR. LARSON: Yes, this was a beta decay then. 
DR. ABELSON: That’s right. 
MR. LARSON: Into plutonium.
DR. ABELSON: Yes.
MR. LARSON: So then you clenched then the existence then of the first identifiable transuranic at that time. 
DR. ABELSON: Yes. 
MR. LARSON: Was there any other workers throughout the world who definitely had also had the neptunium? I believe this was unique. 
DR. ABELSON: No. Yes, this was unique. 
MR. LARSON: Fermi’s claims were all confused.
DR. ABELSON: Were all wrong, yes. 
MR. LARSON: Yes.
DR. ABELSON: It’s interesting incidentally, tremendous, one of the great minds of this generation, got the Nobel Prize for something that was completely wrong. (laughter)
MR. LARSON: Oh, this has happened. I believe once also in the field of biology too. Fortunately that’s a unique happening. 
DR. ABELSON: Well, I went back then to Washington and I found, now remember this was May 1940, and the Germans had done their blitzkrieg. When I got back to Washington at the end of May, I found that the spirit in Washington had changed. The scientists had then agreed that further work on uranium should be done free of scientific publication. 
MR. LARSON: Yes. By that time, had the isotope U-235 been identified as the origin of the neutrons, or what was the status of that? 
DR. ABELSON: At just about that same time, I believe it was again in that spring of 1940, Al Mear had prepared a little bit of U-235 and the people at Columbia had determined that it was U-235 with fission. 
MR. LARSON: As I remember had the Bohr-Wheeler theory predicted that, or something? I’m not sure. I’m a little confused. 
DR. ABELSON: There was a Bohr-Wheeler theory all right. That was the start of the liquid drop model, but it really didn’t…
MR. LARSON: It didn’t point to U-235. 
DR. ABELSON: Not to that, no. Well, so then in view of the emphasis on U-235, it became clear that if you were going to have any kind of weapon development or whatever, from uranium you needed a separated isotope. Along about that time, there was also appointed a uranium committee, the S-1 Committee, headed by Dr. Briggs [inaudible] and Mear too, who is my boss at Carnegie and also Ross Gun and Jessie Beams, the centrifuge [inaudible] from Columbia. Well Ross Gun was interested in uranium because of the possibility of having a nuclear submarine. That was the main focus of his interest.
MR. LARSON: That’s very interesting. In other words it was not primarily as a weapon, but as a source of motive power.
DR. ABELSON: As far as he was concerned that was what he was interested in. and it was only later that the large emphasis completely shifted.  Oh, there was some inkling. I remember in fact being with Louie Alvarez at the student center at Berkeley and Louie had just heard about this U-235 as an isotope and Louie immediately jumped to the conclusion that there was going to be a bomb. So…
MR. LARSON: That’s very interesting. About what month and year was that? 
DR. ABELSON: That was, well it was early. I’m finding it difficult to exactly pinpoint it, but as far as I was concerned, Louie was the first to, there might have been others, but Louie was tremendously imaginative fellow and he really could have been the first. I know that others at Berkeley talked about it also, but it’s fuzzy as to who did what. 
MR. LARSON: Oh yes. 
DR. ABELSON: Well it so happened, you know in this country at that time, there were no more than maybe 100 nuclear scientists. And as far as Washington D.C. was concerned, the Carnegie institution was the sole source of nuclear physics. So it came to pass that I was asked by Dr. Briggs to be his advisor. 
MR. LARSON: Oh yes. That’s very interesting.
DR. ABELSON: So I attended the committee meetings and hearings and when there was some correspondence, I drafted the correspondence for him including a letter to Seaborg granting him some $3 to $4,000 to see if he could isolate some plutonium.
MR. LARSON: Oh yes. That’s a fascinating story. They threw around large amounts of money like $3 to $4,000 in those days. 
DR. ABELSON: Yes and then there were other proposals that came in. Some of which I was asked to go and investigate and some I recommended against, but then what really was a shocker came when there was a proposal made to spend $100,000 on getting the necessary U-308 for a pile. This was a proposal that Seagram backed. I didn’t, this was too big for a mere advisor. (laughter) But that was…
MR. LARSON: That’s fascinating and in those days of course $100,000 did buy a lot of uranium.
DR. ABELSON: It did buy quite a bit.
MR. LARSON: I believe it was less than a dollar a pound, or something. 
DR. ABELSON: It was pretty cheap then. Well that was one way of going and of course Fermi was hopeful that he could get a chain reaction and make some calculations with the graphite and a chain reaction hoping it would go critical. But my interest then turned to possible isotope separation. This really looked like a really, really difficult chore. Up until that time, there had been some separation of hydrogen and carbon, but the idea, the thought of separating uranium isotopes in any quantity that just seemed terribly farfetched. One didn’t know how much would be required for a bomb; the feeling at the time was a few kilograms. Alongside of that, what Fermi had done with some micrograms.
MR. LARSON: Yes. As a matter of fact it must have been a fraction of a microgram that near separated at that time. 
DR. ABELSON: I looked around to see if there was some other method and I encountered some work by some Germans, Krushing and Wertz, who had conducted liquid thermal diffusion on some aqueous solutions and zinc salts. They had gotten some separation, some small separation. And so I thought well I’ll try this with uranium. I built the same apparatus and I tested it out with potassium which I could get [inaudible] and the equipment worked all right, but when I put the uranium solution in, the uranium solution decomposed and all I had at the end of this thing was some sludge at the end of the apparatus. So it was clear that when we’re going to separate the uranium one would need to have a compound of uranium that was liquid. I studied to see what there was and there were some possible organic uranium compounds, but the substance that looked like the most practical was uranium hexafluoride. Well there is no uranium hexafluoride available at that time but in connection with my duties as assistant to Briggs, he asked me to go to General Electric, there was a fellow by the name of Kingston who was attempting to separate uranium by gaseous diffusion in a gaseous column. Well I got up there and I found he didn’t have any positive results to show for it, but in the course of my visit, he showed me a little reaction train in which he was converting uranium to uranium hexafluoride. 
MR. LARSON: Oh yes.
DR. ABELSON: But what he was using was a metallic uranium and he had a fluoride generator. Well I looked at what was happening there and I saw that fluorine went in and there was conversion of that metal to something else followed by a production of hexafluoride. 
MR. LARSON: In other words, there was an intermediary compound.
DR. ABELSON: It was kind of an intermediate compound. So I went home and thought to myself if I could get some kind of intermediate compound that would mean I wouldn’t have to use so much fluorine and so I looked in textbooks and I found out it would be easy to prepare a uranium tetra fluoride, easily made and it meant then that one of the problems with using metallic uranium was it was hard to find. There was hardly any available, but there was some uranium salt. You could get that by the bucket full.
MR. LARSON: Oh yes. As a matter of fact I believe that it got, to make pure uranium got to be quite a problem for production of the pile. At your particular stage, there must have been practically none available. 
DR. ABELSON: Practically none. This was cheap and available. So I decided I would go into the business of making uranium hexafluoride. So, I made my own fluorine generator because in those days there was no supply of fluorine gas. And pretty soon I was making and creating hexafluoride. Incidentally some of the other people like Jessie Beams who separated isotopes on the centrifuge, he needed hexafluoride, and people at Columbia doing experiments on gaseous diffusion they needed some. For a couple of years, I was the standard supplier of uranium hexafluoride. 
MR. LARSON: I’ve never heard that story before and that’s a fascinating thing. There was sort of a blank in the history. 
DR. ABELSON: Ultimately in the post war, I got a patent for my process, which I never got the alleged $1, but the people in, I guess it was Montana, needed a large quantity. I told them the process and they got it. Well, with the uranium hexafluoride, I was then able to make an experiment on liquid thermal diffusion, using that as the substance.
MR. LARSON: Did you have to keep it under pressure in order to keep it at a liquid then?
DR. ABELSON: Yes. Uranium hexafluoride melts at 64 degrees centigrade under a pressure of approximately 2 atmospheres. You have to have it under pressure in order to have it liquid. Well I made one column, a 12 foot column, which I ran at the National Bureau of Standards, then Ross Gunn wanted me to come down to the Naval Research Laboratory so I went down there in June 1941, there were better facilities there for making a longer column and some steam [inaudible] hydro powered by steam. So, I made the longer column and made the run and I finally got a positive result. Then it was a matter of making more columns to determine the optimum separation between walls.
MR. LARSON: What method did you use to assay for the U-235 content?
DR. ABELSON: Well, I had some friends that had a mass spectrometer. 
MR. LARSON: Oh yes. 
DR. ABELSON: And they were kind enough to let me use it. A guy by the name of Ed Nay was at that time at the University of Virginia. I should say just a word about the thermal diffusion column itself was a very simple thing. It consists of a central tube about one and three quarters inches in diameter which is surrounded then by a second tube which is just a little bit larger than, enough larger in diameter to have a space in between the two tubes of about 10,000ths of an inch. Then surrounding the second tube is a third tube for cooling fluid. 
MR. LARSON: Oh yes.
DR. ABELSON: Ultimately we ran at a steam pressure of about 1200 pounds per square inch, which is something like 286 degrees centigrade. The cooling water was maintained at 64 degrees centigrade through recirculation. 
MR. LARSON: Well there was a hot wall and a cold wall.
DR. ABELSON: A hot wall and a cold wall and it took ultimately our units were 48 feet long and it took about 2 days to establish the separation between top and bottom. Our best separation was one in which the bottom was approximately seven tenths percent U-235 and the top was approximately 1.4 percent U-235. That was the very best.
MR. LARSON: If you could do that on a scale large enough going from seven tenths to 1.4 essentially doubles the production of an isotope separation.
DR. ABELSON: Well some of them. it turned out in practice to not be that good, but it was a useful separation. These things were accomplished by myself and one other person, John Hoover who came around at that time. One of the sort of amusing things that [inaudible] had to do with our use of steam. Of course I had had no experience with steam. We started 100 pounds per square inch, and I was scared of that. 
MR. LARSON: Oh yes.
DR. ABELSON: Afraid it would explode. Then once we got some kind of result at 100 pounds. We wanted to see what we could do with a higher pressure. I looked around and saw that I could buy a boiler that could generate 600 pounds. So I got that and we rigged it up and it started to run and we were of course worried about that. When it didn’t explode, I remember we jacked it up to 1200 pounds [inaudible]. For the first 5 or 10 minutes after we jacked it up to 1200 we stood outside of the place waiting for the explosion and when the explosion didn’t occur we relaxed. I clearly remember we were making runs of 20, day and night, the two of us, but somebody had to be around all night so we had the cops next to the boiler.
MR. LARSON: That’s an amazing story. In these days it’s nothing to have 2 or 300 people on a project like this. 
DR. ABELSON: So, we went to, had a number of columns at the Naval Research Laboratory and we actually shipped some of the partially separated material out to Chicago for some tests out there. I never heard what the tests were, but they were glad to have the product. So then, Ross Gunn and the rest of the people were interested in pushing this thing further. So we investigated where we could carry on the work and it turned out that out in the Naval Boiler and Turbine Laboratory at Philadelphia Navy yard, they had some big boilers that were being tested. These were the kind of boilers that might go on a battle ship. So we were able to get authorized to use one of those big boilers and make a plant. So, we got set with the intention of making some 300 columns to operate there. Well the interesting thing, I had about 5 other people that were working for me, but this operation was done with the greatest of secrecy and furthermore at that time, a great deal of battle damage was being sustained to the ships. So there were 23 priorities on the Navy Yard and we were number 23. But we went ahead and made friends with the fleet men and the fleet men had a certain amount of discretion about where they worked and the big operation. It was inevitable that you couldn’t control it precisely. So we were able to entice some of these people to come and work for us. So we got, were able to get as much progress as we increased in priority.
MR. LARSON: All kinds of things were needed to get the work done at that time. 
DR. ABELSON: So well, there were similar things with respect to getting the materials. You had priorities on the materials. You went to the purchasing agent and you gave them and gave them a good song and dance and the friendly fellow who took the purchasing agent out for coffee.
MR. LARSON: Very good. That’s a part of getting a project done. 
DR. ABELSON: Well, so we were now, this was now in the fall or perhaps in January, a little later, the spring of 1944 we had quite a number of columns going. We were producing some partially separated uranium. Well it turned out that at that moment the gaseous thermal diffusion work was not going very well. They were having trouble with the barriers. There was concern that the barriers plugged up and that a gaseous diffusion plant wouldn’t work. On the other hand they had some pretty big steam plants going down there and somehow or other, someone in the Navy was going out to Los Alamos and I remember that I was asked to meet him at one of the theaters downtown and brief him on what we were doing. Just like a spy drama.
MR. LARSON: Oh yes.
DR. ABELSON: Well shortly thereafter, he was in Los Alamos and he spoke with Teller. Teller got interested in this situation recognizing that if we had a partial separation of an isotope this would improve the production of the electromagnetic plant. So Teller went to Oppenheimer and then they talked to General Groves and so pretty soon in a room at the Naval Research Laboratory it was agreed that this thing should be integrated into the complex at Oak Ridge. One slightly unusual thing about it, you know General Groves was a stickler for security, so he visited the installation group, but later he sent around some security officers from the Manhattan District to see what, if there was adequate security at the Navy yard. Well these fellows arrived at the portals at the Navy yard and they identified themselves to the officer there and they said they wanted to see this instillation, well the Navy officer didn’t know what the hell they were talking about. (Laughter)
MR. LARSON: Well, that was a good sign for security. That was the best recommendation your security could have. (Laughter)
DR. ABELSON: We had succeeded in building up quite a plant in the Navy yard without anybody knowing about it.
MR. LARSON: Wonderful.
DR. ABELSON: Well so the, immediately of course there was an effort to build the plant rapidly. Colonel Mark Fox was the officer in charge for the Manhattan District. He was a real go-getter. They had a plant essentially completed in 75 days. You know you remarked that Colonel, General Nichols said it was 4 months from the start. Well, I would defer to General Nichols on this. 
MR. LARSON: Well actually a fair amount of production was coming out. So it was construction plus initial production of this. 
DR. ABELSON: Well, I think that the cost of the plant was something like $8 million, I forget now; it might have been $10 million or something like that.  Following the war, there was a congressional declaration in which it was said that that plant had shortened the war by 8 days.
MR. LARSON: I’ve heard various estimates. It was 8 or 30 or someplace in between, but I think the important point is it did increase the production of the electromagnetic plant by 25 to 30 percent. I believe as soon as your beam for the thermal diffusion came in, you increased the isotope concentration from seven tenths to over nine tenths per second.
DR. ABELSON: Well it was something like that.
MR. LARSON: That’s 25 percent roughly.
DR. ABELSON: Of course another facet is that if you start out with pure material you wind up with pure material. So you get a little bit extra benefit.
MR. LARSON: Oh yes. 
DR. ABELSON: Well so, that was essentially it. Of course the gaseous diffusion did get into operation. We licked those problems and at the war’s end, they didn’t have a need for all the power they could get at the power plants. So these liquid thermal diffusion plants were shut down and made into scrap. Well the Navy was still interested in the submarine, possibility of submarine propulsion so I was asked to look into it. I already knew that with a somewhat separated uranium isotope, the size of the reactor could be remarkable smaller. The prospects were pretty good to do something like that. So I spent about a half a year at Oak Ridge at the X-10 plant and familiarized myself with the reactor matters. 
MR. LARSON: That was before that famous first class in reactor technology that was developed by Rickover and some of them. 
DR. ABELSON: Oh yes. This was in the winter of ‘45, to ’46.
MR. LARSON: Yes. It wasn’t until ’47 the class was actually, I believe, actually started. 
DR. ABELSON: At that time, of course, had come available some designs, some German designs of their best submarines and so we took those blueprints and replaced the conventional weighted machinery with a corresponding weight of a nuclear reactor. Changing the shape somewhat to improve the shielding, but it essential maintained its buoyancy. This showed that it was a feasible thing to do. As it turned out we used a liquid metal cooled reactor, and Rickover wisely chose the water cooled, because the liquid metal cooled didn’t prove out. Well, it proved out recently. 
MR. LARSON: That’s right. It’s proved to be very successful compared to what it had been.
DR. ABELSON: But in those early days it looked good at the end of ’45, but then later on some problems developed. Well, I then decided that actually to proceed further with a nuclear submarine was going to require a highly placed Navy officer. The Armed Forces during the war were marvelous to work with, particularly the Navy, but at the conclusion of the war, the pace and the whole spirit changed and I knew it was a different ball game. So I decided I would go back to civilian efforts and I further decided that I did not wish to participate in the high energy physics. I felt then as I do, that the high energy physics was not going to lead to practical applications. 
MR. LARSON: Oh yes. And you had come to that realization way back in 1946. It’s proved correct. 
DR. ABELSON: I decided then and I decided I would gamble on something else. Actually what I chose to gamble on was biophysics. A feeling that the tools that had been created, the artificial radioactivity, and so on, was going to enable people with a physics background and work rather advantageously in biology. So in due course I had a crack at molecular biology and the form our efforts took were to study the biosynthetic pathways of the microdot.  
MR. LARSON: Was this work carried out at the Carnegie Institution?
DR. ABELSON: Yes, this was carried at the Carnegie Institution, and we in due course in about 1953 prepared a book that has since then been kind of a Bible for microbiologists. In fact some of the people that are growing [inaudible] E. coli at this time, routinely splicing have that as a useful part of their library.
MR. LARSON: In this particular effort did you make use of some of the radio isotopes like carbon-14, and so on as one of your tools?
DR. ABELSON: Oh yes, we used carbon-14 and also among other things, we made carbon-14 tagged sugar by using leaves to photosynthesis the sugars. 
MR. LARSON: Oh yes. So you actually created some very complex molecules out of the carbon-14.
DR. ABELSON: And we had an interesting scheme was that we found that the microorganisms are, shall we say, lazy. They won’t make something if it’s fed to them. That is we found that if we could make a good contest to an intermediate that involved in the formation of a protein that if we put that intermediate in a solution then that protein would not be radioactive. The amino acid would, the protein would not be radioactive. So we were able to then to trace in great detail the whole action of the microorganism as a chemical engineer, just what were the particular steps used in making all the major products. 
MR. LARSON: Well, this is sort of the, essentially the start of a big revolution in biology to have those techniques available.
DR. ABELSON: Yeah, well we weren’t the only ones. When we began there were very few people into it. Of course now anyone, it’s absolutely commonplace now. At that time, the biochemists and biologists were slow to see the radiation effects. Well about 1953, I was approached by [inaudible], he asked me to be director of a geophysical laboratory. Well I hadn’t had of course geology, of course its physics, but I thought I might be interested. So I became the director. Well I then decided that I needed to have some sort of research group of my own and I had been working with amino acids and I knew how to isolate them and so on. So I decided that [inaudible] if some of the fossils lying around had amino acid in them, traces of patterns in biochemistry. So I went down and collected some fossils in Chesapeake Bay and brought them back to the laboratory, processed them, and sure enough there were amino acids in the fossils. Some of the amino acids were more stable than others. So those were the ones that remained. I did some physical chemical studies on the stability of the amino acids and the ones that had long endurance of the fossil were certainly stable. 
MR. LARSON: What were some of the more stable amino acids? 
DR. ABELSON: Alanine, lanine [phenylalanine], and glycine. The ones that weren’t stable were serine and threonine, they have... You know once you find out which are stable and which aren’t stable, you…
MR. LARSON: Yeah, you have a hydroxyl group or something like that…
DR. ABELSON: A hydroxyl group…
MR. LARSON: It makes it easier to break it down, so to speak.
DR. ABELSON: Well…
MR. LARSON: That’s a fascinating thing there. Of course there has been a lot of work since then finding amino acids and speculating on their role and all that. 
DR. ABELSON: Yes, there has been a good deal of that. I also did something else that was to make some studies on the origin of petroleum and I pretty well convinced myself on how that happened. When organic matter falls into an anaerobic environment then it can no longer be affectively be attacked by the microorganisms and then when it is subsequently buried, gradually the temperature to which it is exposed rises and the problem is the effects on the temperature then to break down the petroleum product. Now I wasn’t the only one to have that idea of the, some of the people in the petroleum companies do working with it weren’t saying anything. 
MR. LARSON: Oh yes. 
DR. ABELSON: In fact, some of the companies lost many hundreds of millions of dollars drilling into formations that weren’t warm enough to make petroleum.
MR. LARSON: Oh yes. Well that was a definite scientific fact that the petroleum companies had better pay attention to.
DR. ABELSON: Well, they’re wise now. 
MR. LARSON: Oh yes.
DR. ABELSON: So that was basically the last of my laboratory efforts. 
MR. LARSON: Well fine. I think that, of course you have a large number of other experiences in advising on National Science Policy and other things like that, but I guess probably that would be a whole other story so to speak.
DR. ABELSON: Yeah, that’s right. I was onetime president of four organizations simultaneously.
MR. LARSON: Wow.
DR. ABELSON: Including the International Union of Geological Sciences. So I participated in quite a few of the societal and other matters. 
MR. LARSON: Well this is an amazing story of the versatility that your interests have taken you to and it was, that’s a very fascinating story. So I think we, do you have any other things that you wish to add at this time? 
DR. ABELSON: No, I’ve said enough. 
MR. LARSON: Fine. 
[End of Interview]