Maker of Patterns

by Freeman Dyson

  So, finally, to Chicago, where I arrived on Wednesday. I am staying at a big, cheap, and very nice YMCA hotel, in the centre of the city and with one block of buildings and a few hundred yards of park between me and the lake. Since I arrived the sun has been shining and a cool breeze has been blowing in from the lake, and I feel I could very happily stay here indefinitely. There is an excellent art gallery nearby, at which I spent a long time yesterday; also bookshops, theatres, a zoo, and an endless variety of park benches. The city is noisy (they have still an elevated railway), but I am twelve floors up and not bothered by it. Above all, it is the lake which makes the city so pleasant. Because the waterfront is not taken up like New York’s with docks, the lake is accessible. To walk through the centre of this city makes a very fine object lesson in the mutability of human affairs. Among the skyscrapers and the boulevards and the department stores, you come to a little monument which reads “On this spot stood Fort Dearborn, which in 1812 was attacked and besieged by British troops. The garrison, having made an escape by night, was afterwards brutally massacred, together with its women and children, by Indians.” And a little further on is another monument which reads “On this spot in the year 1805 was born Helen, the first child to be born in the city of Chicago.”

  JULY 22, 1948, ANN ARBOR

  I have met here a graduate student called Park who was working in the U.S. Eighth Air Force Operational Research Section at High Wycombe while I was at our Bomber Command. We may even have met there, though we don’t remember. This gives us a lot to talk about. Park is a most intelligent man. He has a young wife who is going this week to Philadelphia as one of the thousand-odd national delegates to the Third Party convention. She treats this as rather a joke, but still she must have worked hard to be given such a position. She is delegate for a sizeable part of Michigan. It is good that the Third Party should be preaching its ideas vigorously, even if one does not believe that they could do much were they in power.

  The Progressive Party, led by Henry Wallace, had split off from the Democratic Party led by Harry Truman. It attracted young idealists like Clara Park who found Truman too belligerent. There was also a fourth party, the Dixiecrats, who were Southern Democrats fighting to preserve racial segregation. In spite of the four-way split, and to everybody’s amazement, Truman won the election.

  AUGUST 8, 1948, ANN ARBOR

  The great event of the week was the birth of Ed Lennox’s first, and Helen’s fourth, child. It arrived early on Monday morning and gave very little trouble to anybody. I went to see Helen and the baby yesterday. She is in a very nice small maternity hospital, which is part of the university medical school, and she gets everything done there for a total fee of $120 because Ed is on the university staff. Helen was completely well and walking about the room. Ed is very pleased because the baby has already a nose like his, whereas the other three children still have no noses worth speaking of.

  When the baby arrived and turned out to be a boy, Ed asked his daughters Nena and Caroline what he should be called, and they replied immediately, “Nicolai.” So Nicolai he is. The other night I had supper with the Lennoxes and spent a happy hour fighting with Nena and Caroline. I like them very much, and what is more surprising, they seem to like me. Caroline even came back afterwards to kiss me goodnight, an entirely unexpected honour. Caroline, just five years old, is showing many signs of awakening character and intelligence. The other day when she was alone with Helen, she asked for the first time the difficult question, how it was that the first baby got born, since all babies nowadays seem to have mothers to bear them. Helen was not prepared for this and, being a Catholic (though not a very devout one), fell back on the first thing that came to mind and told her the story of Adam and Eve. Caroline listened to this intently, thought it over for a while, and then pronounced, “Well, that is a funny story.”

  My days here have been spent going to lectures, working at my own ideas, and reading and talking. I have met a lot of new faces, but most of the time I am with Lennox and Wergeland. The young Mrs. Park came back from the Wallace convention. She told us all about it, and confirmed the picture drawn in the newspapers. The important question we wanted answered was how far the party is in fact Communist and how far merely liberal. She said that she found most of the delegates, like herself, young and enthusiastic and liberal and not noticeably Communist, and this was her prevailing impression of the party as a whole at first. However, toward the end of the convention, a delegate proposed a crucial amendment to the party platform, which ran, “While deploring the foreign policy of the U.S. this Party does not necessarily endorse the foreign policy of any other country,” and this amendment was defeated by a majority vote. Mrs. Park said this was evidence that at least a good proportion of the delegates were Communists, or at least were making no effort to avoid being labelled as such. She continues to work for the party; she says she does not like being used by the Communists, but she prefers that to being used by their enemies. The tragedy of the Wallace party is not that it is being used by the Communists. It has now lost what was at one time a good chance of winning enough popular support to be a strong force in the land.

  AUGUST 15, 1948, ANN ARBOR

  After nine days in hospital Helen Lennox and the baby came home and are both doing well. Ed recently had a letter from Hans Bethe, who is enjoying himself enormously in his old haunts in Switzerland. He finds it a paradise. I think he suffers in the U.S. from the fact that he is unable to shake off the millstone of Bomb work and responsibility from his neck. It is years since he had a long and complete vacation. Also, he came to Switzerland fresh from Germany, which he found a nightmare. In Germany he was visiting his family, and a family reunion across such a gulf of years and circumstances is a psychological ordeal for all concerned.

  My correspondent Hilde Jacobs at Münster has got a permit to work in Switzerland for three months this autumn. This should be a tremendous help to her, both physically and mentally; I hope soon to hear her initial reactions to it. She and I have been getting to know each other pretty well in the last six months. It all began when she wrote to me last Christmas, and I knew then at once that she wanted more than food parcels; she wanted sympathy, companionship, and above all, hope. After thinking it over, I decided that the best I could do for her was to give her all I had and let the consequences take care of themselves. So without making any commitments or promises, I have been writing to her from time to time, letters of various kinds and on various subjects, always with a certain deliberate warmth of feeling. This has been a great pleasure to me, but I think I can say also that it has been justified by its effects on her. She seems to have grown happier and more balanced in these months.

  I tell you about this rarefied flirtation that has been going on across three thousand miles of ocean, so that you should know who this girl is if I ever invite her for a holiday in England. That is something that I would not do without much more thought and consideration. I think she herself expressed the dangers of the situation better than I could ever express them, by quoting Yeats:

  I would spread the cloths under your feet,

  But I am poor, and have only my dreams.

  I have spread my dreams under your feet;

  Tread softly, because you tread on my dreams.

  Whether a girl, to whom English is a foreign language, could know not only how apt but how good a stanza that is, don’t ask me!

  The Yeats poem “Aedh Wishes for the Cloths of Heaven” (1899), has only eight lines. The first four lines are also worth quoting,

  Had I the heavens’ embroidered cloths

  Enwrought with golden and silver light,

  The blue and the dim and the dark cloths

  Of night and light and the half light,

  (continuing into the lines that Hilde quoted).

  AUGUST 20, 1948, SAN FRANCISCO

  I left Ann Arbor at nine on Monday morning, taking a bus direct for Chicago, and caught the westward express that evening. The route went thro
ugh Illinois, Iowa, Nebraska, Wyoming, Utah, Nevada, California; one state north of my previous excursion. As far as the end of Nebraska this was the corn belt, and a bumper corn crop at that. We went through Iowa through field after field of corn, the fields not being very big but all uniformly tall, tassel-topped, and lusciously green. Between the cornfields are grazing plots where cattle are either raised or brought in from the west for fattening on the corn.

  The real prairie begins only in Wyoming, and there does not last long before it fades into mountain ranch country and finally desert. The most spectacular part of the whole trip was our descent, down the Weber River valley, from the Wyoming desert into the basin of Utah. Here we were following the route of the 1847 pilgrims, which made it all the more dramatic. The Utah basin is not all fertile, but for long stretches round the edge, and in the gorges leading out of it, the rivers have been put to work and the land cultivated intensively. Only in Switzerland have I seen such painful utilisation of every scrap of mountainside. The effect of this careful husbandry, after the wastes of Wyoming, is greatly to increase one’s respect for the Mormons. I think it is typical of them that on their first terrible journey across the mountains, Brigham Young attached a newly invented revolution-counter to the wheels of his oxcart so that he could navigate with greater precision.

  In Salt Lake City we stopped for two hours, so I was able to take a rapid glance at the historic monuments. Of these the most interesting was a column set up in 1897 at the fiftieth anniversary of the founding of the city, with the names of 143 original settlers engraved on it. Of the 143, twenty-seven were then still alive. Their skill in dealing with natural obstacles, Indians, and their own private quarrels was altogether exceptional. Utah now, with its mixture of small subsistence farms and industrialised cities, its non-Mormon minority of 40 percent rapidly turning into a majority, will inevitably lose much of its homogeneity and character. But it still remains a strong example in favour of Toynbee’s thesis that in the long run religion counts for more in human history than any other single factor. Comparing the achievements of the settlers in Utah and California, who were building their civilisations at the same time, one feels that Utah achieved greatness while California had greatness thrust upon it.

  AUGUST 26, 1948, BERKELEY

  Today I saw a scientific miracle which assuredly will turn the world upside down, perhaps even save our lives; one of the great discoveries which, like most such, can be understood by everybody. So I will tell you about it while it is fresh in my mind. It will do for biology what the Wilson cloud chamber did for physics. It is essentially just a gadget, like the cloud chamber which provided the essential tool for the development of nuclear physics. In a letter some months ago I spoke of the work being done at this university on the problem of photosynthesis. Today I went to a lecture by Professor Melvin Calvin, the leader of this research; he is a small, middle-aged, but very able-looking man. He was speaking about the most recent results, which were not known when I wrote before.

  The cloud chamber is a box full of humid air which can be expanded rapidly. After the expansion the air is temporarily supersaturated, and the excess moisture slowly condenses into a cloud of droplets. If the box is illuminated with a flash of light and a photograph is taken immediately after the expansion, the photograph shows visible tracks made of droplets that condense around any rapidly moving nuclear particles. The visible tracks show precisely where nuclear particles are traveling through the air, and where they are occasionally deflected by nuclear interactions. The cloud chamber was invented by the Scottish physicist Charles Wilson in 1911 and was the main tool of nuclear physicists for many years. In a similar fashion, Melvin Calvin’s invention of tracer chemistry allowed him to make visible the rapid chemical reactions that occur in a green plant when a molecule of carbon dioxide is absorbed from the air and converted by the energy of sunlight into sugar.

  The method Calvin uses is the following. You take a large white sheet of blotting paper; on one corner of it you place a drop of liquid, for example the juice of crushed seaweed cells, and let it dry. Then you fix the sheet so that it is hanging vertically with two edges horizontal, and the upper horizontal edge you fasten into a bath of some oily liquid like phenol. The phenol slowly trickles down the sheet, and you let it trickle for some hours. Then you take the sheet out and dry it again. The substances contained in the original drop of juice will be left on the sheet, but they will be carried down by the phenol along a line along one edge. The different substances will get carried down various distances according to how great an attachment they have for phenol. Now you fix the sheet up again, with the edge along which the drop is spread now horizontal and uppermost (i.e., at right angles to its previous position), and let a second oily liquid (not phenol) trickle down it for some hours. Then you dry the sheet a third time. Holding the sheet in its original position, each substance in the cell juice has been carried a certain distance down the sheet by the phenol, and a certain distance across the sheet by the other liquid. Now the remarkable fact is that, if you use the right sort of paper and the right sort of liquids and the right speed of trickle, the various substances in the juice get cleanly separated from each other, and each substance does not get smeared out much but remains as a small splodge at some point on the sheet. These splodges cannot be seen except for the most brightly coloured substances. But suppose that your seaweed has been feeding on radioactive carbon dioxide (made now in adequate quantities in a pile). Then all the substances in the juice contain some radiocarbon, and if you put your sheet of blotting paper against a sheet of photographic film, you get a picture with all the splodges in their respective places.

  Now comes the decisive step. Suppose you have a series of samples of seaweed which are not radioactive, having been fed on ordinary carbon dioxide. The first sample you plunge into radioactive carbon dioxide for five seconds, then quickly crush the cells and extract the juice. The second sample you give ten seconds of radiocarbon, the third thirty seconds, the fourth sixty, and so on up to as long as you like. Each sample of juice is then put on blotting paper and photographed. The pictures then show, in the most direct possible way, the progress of the delicate and transitory reactions through which the radiocarbon passes as it is assimilated. After five seconds the radiocarbon is all in one or two substances, after ten seconds in four, and after thirty seconds in ten, and after a minute it has got into the splodge which contains sugar, the final product of the reactions. (This is contrary to all the old theories of photosynthesis.) Before you can interpret the pictures, you have to know which splodge is which. For this it is necessary to go through a long and laborious process, preparing every known constituent of the cells, isolating it chemically, and including in it a sufficient quantity of radiocarbon; then the isolated substance is put onto the blotting paper, and you can see where it ends up. In this way each substance can be identified with a definite position on the picture, and once the identification is made, it is done once and for all; these identifications are taking up most of the time of the workers at present, but later on this will not be necessary.

  This simple technique is an immense advance, enabling people to accumulate in a few hours detailed information which before could hardly have been reached in years. Instead of carbon, you can use any other radioactive atom, and you can vary your trickling liquids to suit your conditions. The results that have been got so far are trifling in comparison with what will be done in a few years. The long-sighted people said, when nuclear energy first came on the scene, that the application to biological research would be more important than the application to power. But I doubt if anyone expected that things would get going as fast as they have. This blotting-paper-plus-radioactivity technique is revolutionary because it means that any substance can be fed to a cell and its transformations followed second by second in detail, even in quantities too small to be seen or weighed, and with substances too unstable to stand old-fashioned stewing and chemical extraction.

  Melvin C
alvin won the Nobel Prize for Chemistry in 1961 for this work.

  SEPTEMBER 14, 1948,

  17 EDWARDS PLACE, PRINCETON

  Today I registered for the U.S. armed forces, as I have to do under the recent draft act. This is nothing to be alarmed about. The point of it is to catch aliens who are permanent residents of the United States. I said, if I am called up, I will join the air force and hope to get stationed in England.

  After I wrote to you last, I stayed several days in Berkeley. I read the autobiographies of Jawaharlal Nehru and Oliver Lodge, both very interesting stories. On September 2 I finally boarded the bus for Chicago, going back by the same route on which I came. The Iowa corn was now standing eight feet tall, having greatly benefited by the recent heat and rain. It was still not quite ready for reaping. Out of Iowa (not a big state) comes one-tenth of the whole food output of the United States. Corn is an immensely prolific crop to grow, and you have only to look at an Iowa cornfield to feel this. It is a great pity the stuff will not grow in England.

  On the third day of the journey a remarkable thing happened; going into a sort of semistupor as one does after forty-eight hours of bus riding, I began to think very hard about physics, and particularly about the rival radiation theories of Schwinger and Feynman. Gradually my thoughts grew more coherent, and before I knew where I was, I had solved the problem that had been in the back of my mind all this year, which was to prove the equivalence of the two theories. Moreover, since each of the two theories is superior in certain features, the proof of equivalence furnished a new form of the Schwinger theory which combines the advantages of both. This piece of work is neither difficult nor particularly clever, but it is undeniably important if nobody else has done it in the meantime. I became quite excited over it when I reached Chicago and sent off a letter to Bethe announcing the triumph. I have not had time yet to write it down properly, but I am intending as soon as possible to write a formal paper and get it published. This is a tremendous piece of luck for me, coming at the time it does. I shall now encounter Oppenheimer with something to say which will interest him, and so I shall hope to gain at once some share of his attention. It is strange the way ideas come when they are needed. I remember it was the same with the idea for my Trinity Fellowship thesis.