[Cover of Sullivan's book 2009, Cosmic Noise]
Sullivan's Cosmic Noise, Cambridge University Press, 2009


NATIONAL RADIO ASTRONOMY OBSERVATORY ARCHIVES

Papers of Woodruff T. Sullivan III: Tapes Series

Interview with John G. Davies
At Groningen
12 August 1978
Interview time: 30 minutes
Originally transcribed by Pamela M. Jernegan (1979), retyped to digitize by Candice Waller (2016)

Note: The interview listed below was originally transcribed as part of Sullivan's research for his book, Cosmic Noise: A History of Early Radio Astronomy (Cambridge University Press, 2009). The original transcription was read and edited for clarity by Sullivan, retyped to digitize in 2016, then reviewed, edited/corrected, and posted to the Web in 2017 by Ellen N. Bouton. Places where we are uncertain about what was said are indicated with parentheses and question mark (?).

We are grateful for the 2011 Herbert C. Pollock Award from Dudley Observatory which funded digitization of the original cassette tapes, and for a 2012 grant from American Institute of Physics, Center for the History of Physics, which funded the work of posting these interviews to the Web. Please bear in mind that: 1) This material is a transcript of the spoken word rather than a literary product; 2) An interview must be read with the awareness that different people's memories about an event will often differ, and that memories can change with time for many reasons including subsequent experiences, interactions with others, and one's feelings about an event.

Click start to listen to the audio for tape 112B of the 1978 interview.

Begin Tape 112B

Sullivan

This is talking with Professor J. D. Davies at Groningen on 12 August 1978.

Davies

We started, as I say, very soon after the War. I got to Jodrell in the beginning of 1947, it had been going about one year.

Sullivan

What was your training?

Davies

I was an engineer; I was trained at Cambridge in 1942-44 and then a couple of years in the government in wartime developments.

Sullivan

But in what field? Physics?

Davies

No, in radio. And I heard about this group and I wanted to get back into universities and, more or less, by chance joined it and stayed with it, first in meteors and then in astronomy.

Sullivan

You had no particular interest in astronomy?

Davies

A general one. It struck me as a good and interesting thing to do.

Sullivan

And so when you got to Jodrell in 1947, what did you find was going on?

Davies

I think it was entirely meteors at that time, although solar work started on small scale and then fairly rapidly moved out into other things as well. Meteors was mainly worked by Clegg in those days on meteor radiants, the directions from which meteors were coming. And following an idea by Herlofson, a Norwegian who was with us in Manchester at the time, I started developing the meteor velocity experiments.

Sullivan

Doing Doppler - ?

Davies

Itís not Doppler, no itís a Fresnel diffraction pattern that you measure as the trail is formed. The trail is an ionized line which is formed linearly Ė when it crosses the rectangular point, you get a Fresnel diffraction pattern. To measure it, you have the range and the wavelength and the scale of the pattern gives the velocity.

Sullivan

I see.

Davies

And two or three years after that, we developed it into a direction as well by having spaced stations on the ground. It was not an interferometer in the radio sense, well, it was the effect of the interferometry on the, youíve got three diffraction patterns and the displacement of these Ė

Sullivan

Triangulation.

Davies

Yes, the displacements of the diffraction patterns give the vectors of the direction as well as the velocity.

Sullivan

Could you have done Doppler in those days, or was this a more sensitive technique?

Davies

You saw Doppler as well at the low frequencies, but we were tending to be at a higher frequency and Doppler only occurs on the strong echos, whereas the diffraction, the Fresnel pattern, appears mainly on the weaker ones. So they were complementary techniques, but -

Sullivan

But the Doppler, when did that finally get going in the field?

Davies

It needed more powerful, but as I said, it observed different meteors. You get the Doppler only on the ones with an over-dense head which you see approaching you, and perhaps receding as well, while the diffraction technique operates on under-dense trails (by the way it penetrates the whole trail).

Sullivan

I see.

Davies

And it acts on a different class of meteors, smaller meteors.

Sullivan

So they were nicely complementary?

Davies

Yes, yes.

Sullivan

What was the physical situation at Jodrell? Were they still in the caravans in the fields Ė

Davies

Oh, yes.

Sullivan

In 1947 when you got there?

Davies

Yes, for several years. 1950 we had the first permanent building.

Sullivan

I see, so it was very much a field station.

Davies

It still is in that sense, we have a lot of country around, but weíre civilized in the sense of having buildings.

Sullivan

And also, it was only a single group working on a single problem Ė very different from what it later became, is that correct?

Davies

Well, it was split into a group measuring directions of radiants, (?) and a group measuring velocities, and then there was another group which actually measured the Doppler on the established trail, which measured upper atmosphere winds.

Sullivan

I see; could you just tell me who were in those groups?

Davies

Clegg in the early days, and then there were Ellyett who went back to New Zealand and carried on there with meteor work in the Southern Hemisphere. Greenhow, whoís dead now, was the chief man on winds, upper atmospheric winds.

Sullivan

Ionospheric?

Davies

Yes, he was measuring wind velocities in the ionosphere. Hughes, who is now in Canada, worked on the radiant side for a while, and then moved over to the astronomy. Itís hard not to forget people. And Hanbury-Brown, of course, came fairly soon after this.

Sullivan

Right, but he never really got involved in the meteor work.

Davies

Not in the meteor side, no.

Sullivan

Which was Lovellís primary interest?

Davies

It was meteors to begin with.

Sullivan

But I mean, which of these groups or was he just supervising them all?

Davies

I think he was supervising them all. Well, his particular interest, and mine also, was the question of whether -

End Tape 112B

Click start to listen to the audio for tape 113A of the 1978 interview.

Begin Tape 113A

Sullivan

This is continuing with J.G. Davies on 11 August, 1978. This question of -

Davies

Twelfth.

Sullivan

Twelfth, yes. This question of the origin of the meteors, could you go into that? How did the problem come up?

Davies

Well, it came from the optical observers, and there were two sets of optical observers who had made measurements of the velocities of meteors by various techniques, estimating the speed across the sky and the distances. One of these was Öpik, who first in Estonia and then in Northern Ireland, had a technique which indicated that many meteors were moving much too fast (?) the solar system and had hyperbolic orbits. Then there was Hoffmeister at Sonneberg from Eastern Germany who had the opposite view.

Sullivan

Were they using different techniques?

Davies

They had differing techniques, they both sounded good, but one had a locking mirror, and you saw the meteor path through and this sort of thing as you looked down - and optical effects, physiological effects, I suspect. There was no photography, direct photography wasnít possible. And made this suspect. Now we therefore set out to measure the velocities, and if we could get directions as well, then this was even better, but initially only velocities with more directions. You had a narrow beam, the meteor had to be perpendicular to that beam, one but not two dimensions, coordinates for its direction. And using that technique, we could find no evidence for more than (?) observational errors over the limiting, parabolic velocities.

Sullivan

Which is what, 45?

Davies

42, relative to the sun, but then the earth has a velocity of 30, so -

Sullivan

Right, so you had to take that into consideration.

Davies

You get there if they are moving in opposite directions, but you have to set the (?) per second, but you knew the direction of the earthís motion, and you knew the direction you were looking, so you could do some geometry on it, of course. When we had the three station system measuring actual directions as well as velocities, then of course, we could measure the orbits of individual meteors. And still, as my thesis was on -

Sullivan

Oh, I see, you did a thesis at Jodrell.

Davies

My thesis, was at Jodrell, was on meteors.

Sullivan

And when was that awarded?

Davies

1951-52, something like that, I donít know. The conclusion certainly was that there was no evidence for a significant proportion of hyperbolic orbits Ė we measured a thousand or something like this, and none of those were any marginally beyond experiment errors.

Sullivan

Were you in contact with Öpik and Hoffmeister?

Davies

Yes, both of them. As far as one could communicate with Eastern Germany, of course. Öpik was a difficult character in some ways. Hoffmeister was a nice chap, I have gone over and have seen him, heís dead now, but I met him over there. We got on, we had communication with both of these. We also had active communication with an amateur group in England led particularly by Prentice, who were making optical observations, and indeed they would often come to Jodrell and make simultaneous observations so we could relate the meteor echo with the particular visual characteristics, and this was very important.

Sullivan

Now what did Öpik and Hoffmeister think? Did they visit Jodrell themselves actually in these days?

Davies

Öpik certainly did, Hoffmeister never.

Sullivan

Did he sort of look around and ďharrumphĒ and say, ďWell, this is not astronomy,Ē or was he seriously trying to figure out exactly what you were measuring?

Davies

I think that Öpik was quite an old chap by then, and heíd had a very hard life. Heíd lost all his records in getting out of the East, and he never really accepted that our measurements could be good. We must be missing it for one, and he searched for methods of saying why we were not seeing the many hyperbolic meteors which had to be, according to his theory.

Sullivan

Oh, I see, you were missing them.

Davies

We were missing them somehow. He didnít say we werenít making a good observation.

Sullivan

And did he publish this sort of argument also?

Davies

Yes, he must have, I couldnít cite it though.

Sullivan

What about other optical astronomers, or I guess since you were just in meteor radar -

Davies

There was a conference in, must have been 1949, in Manchester. I guess Itís been published in Reports on Progress in Physics.

Sullivan

I see.

Davies

Which Öpik attended, I remember this. On meteors. I think youíll find something there.

Sullivan

Ok, Iíll check that. Now, of course, you must have been educating yourself all this time in astronomy.

Davies

Oh yes, oh yes.

Sullivan

How did you do that? Just reading materials, or ó

Davies

I suppose partly. We are, of course, part of the Physics Department in Manchester, and in those days under Blackettís direction. He supported us very greatly and of course, the department was expanding rapidly after the War, which gave great opportunities. And it was not long after that, a year, I canít remember exactly when, when the chair of astronomy was established there. Largely it was the idea that it would support the work going on at Jodrell Bank. And so we had in the early days, we had many lectures from Professor Kopal, who took up that chair -

Sullivan

Oh, yes.

Davies

(?)

Sullivan

Was he in the physics department actually?

Davies

He was an astronomer, oh yes. Originally in Czechoslovakia, then heíd been in the States for some time and he was first optical in that chair and still is, in fact. And he taught us basic astronomy Ė very well, too.

Sullivan

Now, as you look back, in the late forties, when there was a group, I guess, a staff of ten or something like that?

Davies

I suppose so, yes.

Sullivan

And then, of course, in the early fifties Hanbury-Brown came and others and there were more students, did the nature of the place change, would you say?

Davies

Oh yes, it must obviously, as it grew, and grew more permanent, it changed somewhat, but -

Sullivan

How would you characterize the important changes?

Davies

Well, in the early days if you wanted to do an experiment, or a student was going to write his thesis on a particular thing, you would spend the first year building the equipment, and then youíd do an experiment. As time goes on, of course, you get more and more of the equipment given to you, which has some advantages and some disadvantages as well. Some students never understand what the equipment does, but thatís an inevitable feature.

Sullivan

Was this process already beginning in the early fifties, are you saying, or was that somewhat later?

Davies

Yes, it was. Because even a meteor radar is a fairly complex thing, and parts of that were given. For example, the precise recording technique required for producing the diffraction patterns that I was interested in had to be developed, and so on.

Sullivan

A question which we havenít touched on is the origin of the equipment that you did have in the late forties, was it all military surplus?

Davies

Yes, it was military surplus Ė you could go out and buy a hundred kilowatt transmitter for ten pounds. Provided you towed it back yourself. And the receiver which went with it, which was through the actual equipment, was five pounds. I remember those figures quite clearly. It stopped them from being thrown down old mine shafts.

Sullivan

And how long did this sort of situation continue before you finally had to - ?

Davies

A few years, three or four years I suppose, only you could go on buying surplus equipment from stores for some time after that for a very cheap rate. And a great deal of our early equipment was built on that sort of basis.

Sullivan

But there must have been quite a bit of modification that you had to do for your special purposes, or is that not true?

Davies

Only in the recording. Well, in the control, yes, we made crystal control, pulse generators for example, because the pulse repetition rate was important to us. And the recording devices were special, but the basic equipment, and the telescope, the aerial system you used was special, too. We built a 210-foot parabolic telescope in 1950 with our own hands.

Sullivan

Right. But before we get to that stage, I mean, the earlier meteor radars, were they just once again, just adopted from military sources?

Davies

Oh, yes.

Sullivan

What exactly were they? Just Yagi rays?

Davies

Yes, Yagi rays were what we used.

Sullivan

Okay, so what was it that made the group decide, apparently, that more needed to be done than just meteor radar astronomy? What, would you say, was the thrust? Were you thinking that ďWeíd solved the problems,Ē or - ?

Davies

No, no, really the meteors dropped out because it became less and less compatible to try to do active and passive work on the same site.

Sullivan

I see.

Davies

For a long time, the meteor systems, we had several radars going simultaneously Ė they all transmitted simultaneously. They were all coherent, of course, so as to not interfere with each other. They also produced suppression pulses which suppressed the radio astronomy receivers. And of course, as soon as one started to think about sensitivity in this process, it obviously wasnít a very sensible thing to do.

Sullivan

Time sharing didnít -

Davies

Time-sharing didnít, it got less and less useful, and so we gave that up. But even after that, I went on and did some work, my later papers were purely theoretical calculations on perturbations of meteor orbits and on generation of some rather extraordinary meteor showers. The Giacobinid meteor shower, which produced an enormous number of meteors for about ten minutes in several years, the latest one being in 1946. We were able to show it must have actually come out of the parent comet within about three or four months in, I think, about 1892.

Sullivan

I see.

Davies

We traced it back to an event which must have happened -

Sullivan

And this is an analysis that you did in the late fifties?

Davies

Yes, with (?) who was my student.

Sullivan

But now youíre implying that they, more or less, made you turn your transmitters off, and so you had to turn to theory at a certain stage? Or interpretation?

Davies

Well, by that time we were mainly on radio astronomy, and it was a sort of a lingering interest.

Sullivan

Is this the late fifties weíre talking about now?

Davies

I guess so, yes, late fifties.

Sullivan

In fact, I just talked with John Evans up at Helsinki and he told me about this conflict between the active and the passive people.

Davies

Yes. It went on with the lunar and planetary radar later, rather than the meteors.

Sullivan

A bit longer, yes. So it was a matter, really, that you were transmitting pretty much every day?

Davies

Well, this was survey equipment, yes. And without going continuously, -

Sullivan

It wasnít just a matter that it was just a few meteor showers during the year and you were -

Davies

Well, there were meteor showers when we did constant observations, but much of the observations were survey.

Sullivan

And, of course, you discovered many new one this way.

Davies

Yes.

Sullivan

That, I think, once again, I donít really know that much about that field, I think is one of the most interesting aspects of the whole radar and meteor field Ė just the ability to see the other half of the sky.

Davies

Yes, I think that is a good part of the story.

Sullivan

Well, maybe I should ask you, that and of course, the business about the solar system origin of the meteors which -

Davies

That was probably the best, the most important thing. I mean, the fact that there were meteors in the other half was reasonably predictable.

Sullivan

Yes, but you like to know where they are.

Davies

It was nice to know, yes. And they were somewhat different in character from the night-time ones.

Sullivan

I didnít know that. How is that?

Davies

Well, the night time streams were mainly fairly good and concentrated things, you got a few days regularly; the summer daytime streams, as we called them, was a continuous procession that lasted May through July Ė three months and one radiant came and another one went, it, sort of, moved across the sky with the sun. An enormous area of activity which was more diffuse than the night time showers, and much more long lasting.

Sullivan

And concentrated in those three months?

Davies

Concentrated in those three months. It had peaks in it, of course.

Sullivan

Why is that Ė this annual effect?

Davies

Well, all meteor showers are annual in that the earthís orbit had to intersect the meteor.

Sullivan

No, but I mean, -

Davies

Why in the summer?

Sullivan

Yes, why in those three months?

Davies

I donít think there is a good reason for it; I mean, there is no such thing as, no similar thing in the Southern Hemisphere, in the Southern Hemisphereís summer.

Sullivan

I see. You mean in their daytime showers?

Davies

Yes, they had some daytime showers, but they donít have an enormous concentration, as we did, in their summer months, when a reversed annual effect would be expected as the ecliptic rises and sets in the sky.

[break]

Sullivan

What other important results would you think came out of this meteor radar work either in astronomy or in ionospheric physics?

Davies

I think the physics of the formation of the meteor trail and its recombination was quite important, and Kaiser, who is now at Sheffield, was the chief worker in that field Ė in fact, he still is.

Sullivan

And is it a fair statement to say that these main two astronomical results, once they were established, that the field sort of died out because it wasnít clear what further direction to go Ė in the late fifties, Iím talking about.

Davies

No, the field did go on, not with us. Whipple, in particular, continued both in radar and photographic work. The satellite program using cameras kept making good photographic observations. And that led to actual information about what the meteor was, the sort of particles of which itís made, of which rather little information came from radio, more from the optical side.

Sullivan

Right, but do you agree that the field sort of peaked in the mid-fifties or -

Davies

I think so, yes. I mean, it may be partly a personal view because of - But I think it is less important now, but we had a good time then.

Sullivan

Okay, well, letís go back to the development of Jodrell Bank. The decision to build something like, for instance, the 218 foot non-movable dish, was a decision like this arrived at from a consensus of the group, or was it, sort of, one of the sub-group leaders decided he wanted it and then would go to Lovell and make his arguments?

Davies

It was a small group in those days. Not all the students would be involved in that, Lovell and Hanbury, I think, basically.

Sullivan

And why was there a need felt to do other than meteor radar work, which was pretty exclusively what was done in the late forties?

Davies

I think it was a general interest in expanding into astronomy, using radio techniques in astronomy. It was always there; we started in the meteors, certainly, but we rapidly moved over.

Sullivan

You mean simply that you saw that this was going on and that interesting results were coming out of it?

Davies

Yes.

Sullivan

Do you have any thoughts on why the Jodrell Bank approach tended to be more one of the big dish, not exclusively, but more so than the Cambridge approach where interferometry played more of a role?

Davies

Well, I guess, its partly a personality matter, but also, of course, that nationally you couldnít support two groups doing the same thing, and by choosing different techniques we became complementary groups.

Sullivan

Well, in fact, Professor Lovell made this remark to me that it would be silly, to say the least, for him and Ryle to argue in these national committees.

Davies

Yes, well that was always true, and they came to external agreements about what they were going to do before they went into a meeting.

Sullivan

And supporting each other Ė ďThis year you scratch my back, and Iíll scratch yours,Ē type of thing.

Davies

Yes.

Sullivan

You were never involved in the lunar radar work, is that correct?

Davies

No, no.

Sullivan

Always in the meteors. What, as you look back on the forties to fifties era, what is it that made the radar work Ė well, you made one point about the conflict with the passive people Ė but was that what really made it fade out at Jodrell? The primary reason? What other reasons might there be?

Davies

I think that was the primary reason. It may also be partly chance, with those principally concerned, either leaving or in my case, I wanted to swing over to the other side.

Sullivan

You mean John Evans leaving, and the lunar radar?

Davies

Yes, and Greenhow and Kaiser and so on. They all went on.

Sullivan

And what did your interest switch to, and when did that happen?

Davies

Well, Iíve always had a technical interest as well as an astronomical one. Iím not too sure. I was always concerned with the construction of our large telescopes Ė I was responsible for the control system of the Mark I, which was an analog computer, and then with the digital control for the Mark II Ė I think the first large instrument which had an online computer attached to it.

Sullivan

Now, when was that?

Davies

Well, the Mark I was completed in 1957 and Mark II in 1963. Some four or five years earlier in each case was when it started.

Sullivan

But the difference in the time, was that a matter that many computers had become available on the market so that one could think about doing this?

Davies

Yes, yes. And you see the analog computer was entirely valves, there werenít transistors when we thought about that. And you couldnít envisage using a valve, digital computer, for the reliability problem.

Sullivan

I see.

Davies

So the analog system used many fewer valves, and was adequate and accurate.

Sullivan

You mean the one they used to control the Mark I, for example.

Davies

Right.

Sullivan

Of course, Professor Lovell has written a book about the building of the big dish and we donít need to go into most of the dates and all, but I would be interested in your comments on what were the unique aspects of this design, and what were the basic problems that had to be solved as the design and construction went along?

Davies

Of course, it was the first structure like that, it was made sort of completely tippable. The engineers regarded it as sort of a bridge problem, with the extra dimension of motion added to it.

Sullivan

Well, in fact, Husband, were a bridge building company, but they felt that it was quite do-able?

Davies

Oh, yes. And after all, itís specification was to work at a wavelength of one meter; in fact, we now use it up to about six centimeters.

Sullivan

Meaning that you had quite a bit of tolerance.

Davies

We had quite a lot of tolerance. In fact, it would not work mechanically if you made it as sloppy as the astronomical tolerance allowed. So itís a better instrument.

Sullivan

What were the other considerations that had to go into the design, as far as compromises and so forth? For instance, the feed, the situation where you had to put your life on the line a little bit to get up there, seems to me a little bit strange.

Davies

Yes. Well, I guess we hadnít sort of visualized the problem too much in the early stages, there were various schemes involved and theyíve changed, of course. It has changed quite a lot in the course of time.

Sullivan

Well, in the present version of the telescope.

Davies

Yes.

Sullivan

(?)

Davies

Initially, of course, for long wavelength there was only going to be an open dipole there anyhow, which required very little attention once you had somebody put it there. Now you have to have parametric amplifiers and cooling systems and so on.

Sullivan

Well, thatís true.

Davies

The situationís very different.

Sullivan

Once you were only thinking of just taking the signal down.

Davies

Thatís right, by cable, at least to the base, to the apex of the dish.

Sullivan

This had been done with the 218 foot dish.

Davies

Yes, the same idea. Right.

Sullivan

What about in the pointing control? Was there any particular problems?

Davies

No, I donít think so. It was done with a sort of analog device, using magslip resolvers which produced sine and cosine voltages which were then multiplied and added and so on to solve differential equations. Odd problems, but I think if you go along on the surface and this sort of thing, but theyíre less difficult to solve that way, I think, than a mechanical analog, which can actually jam up.

Sullivan

For instance, like the NRL 50 foot dish.

Davies

Yes.

Sullivan

That brings up another point, about the azimuth-altitude mounting. Were you at all bothered by thins, seeing as, except for the NRL dish, all previous dishes of any size had been equatorially mounted Ė of course, there werenít -

Davies

There was nothing of any size, you see.

Sullivan

Yes, Dwingeloo hadnít even come along.

Davies

Yes, yes. When you got to that size, an equatorial mount was, and still is, quite impossible.

Sullivan

But did this not bother you at all in terms of the disadvantages of the polarization characteristics and possible tracking difficulties -

Davies

No, no. Polarization was a secondary issue probably in those days, and tracking did not seem to be a problem.

Sullivan

Right from the very beginning. Why was it then, I still have difficulty understanding why, for instance, the 140 foot people, which came along many years after your experience, really thought they had to have an equatorial mount.

Davies

I donít know Ė youíll have to ask them.

Sullivan

Well, I havenít gotten a good answer.

Davies

They had more engineering difficulties with that, of course, than we did.

Sullivan

Right.

Davies

Because of that, because of the equatorial mounting.

Sullivan

You think that was the basic problem?

Davies

No, I think itís some and I think the whole bearing problem which they had would not have occurred with an alt-az.

Sullivan

Okay, well are there any other aspects of, in particular, your astronomical career, prior to 1960 or so, that Iíve missed? I donít have, unfortunately, a bibliography for you. Important point, or important points, about the development of radio astronomy in Great Britain that you would like to tell me?

Davies

No, I donít think there was anything else. Nothing startling comes to mind.

Sullivan

One final question. In 19-- well, letís start in the early fifties and then say later on in the fifties, what would you have called yourself, if your neighbor asked you what you did?

Davies

Astronomer.

Sullivan

An astronomer?

Davies

An astronomer, first.

Sullivan

Even in the early fifties?

Davies

Yes, in the early fifties.

Sullivan

Thatís interesting, because most radio astronomers, as we now call them, wouldnít have answered that at that time. Was this because you were working so much in a field related to optical astronomy, perhaps?

Davies

I donít think so, no. Iím surprised at your comment, actually. Maybe it was, I donít think it was true in England, letís put it that way. The optical astronomers had accepted us and did right from the beginning, you know, which was a little remarkable.

Sullivan

Accepted you in which sense? Listened to you at RAS meetings?

Davies

Yes, right. As members of the RAS, we got very full, any paper we submitted, we were asked to read as well, and this sort of thing.

Sullivan

Which were the key people, would you say, in the optical astronomy side, in Great Britain who welcomed in this new field? Because in other countries, there was not always this close cooperation.

Davies

Well, I wouldnít want to mention names, because I think all of them Ė I donít recall.

Sullivan

You donít remember anyone particular who was -

Davies

I donít remember anyone being against it.

Sullivan

I see. Okay, well, thank you very much.

Davies

Not at all.

Sullivan

That ends the interview with J. G. Davies on 12 August 1978.

End Tape 113A


Modified on Tuesday, 07-Feb-2017 15:38:47 EST by Ellen Bouton, Archivist (Questions or feedback)