1 December 1952

Dr. C. Bastiansen

Universitetets Kjemiske Institutt

Blindern, Oslo

Norway

Dear Otto:

I am glad to have your letter about Finbak. Some news has reached me about him, from Ken Hedberg, and also Gunnar Bergmen, who has just returned from a short visit to Stockholm. I hope that his condition continues to improve - I feel strongly that the minimum-protein diet should do him much good, although of course the damage to the kidneys, once done, cannot really be repaired.

I trust that you will send any news that you have about Finbak on to me. Professor Sørensen has written me a letter, containing some information but not very much. I have also written to him asking him to let me know about recent developments.

I have talked with Dr. Lippman about the symptoms that you have mentioned in your letter, and Dr. Lippman has not felt that he could make any definite statements about them. In particular, he said that the indication of mental instability did not have any bearing on the matter of kidney disease, unless perhaps it represented the result of rupture of a small blood vessel in the brain, which might occur because of the hypertension.

I am glad to learn that your new electron diffraction apparatus is working well. The one that is under construction here is still in the shop, and moving along rather slowly. We hope to have it in operation next year.

With best regards, I am

Sincerely yours,

Linus Pauling:W

7 December 1952

Dear Daddy and Mamma,

Here are some problems. If they are too late, I am sorry.

Thank you very much for the gift. Perhaps I shall buy a tuxedo. I must go to dinner with Bragg Tuesday and must rent a dinner jacket. You have ruined all my not very well planned plans to extort great quantities of money. I cannot very well now. As you know, Mamma sent me $100 to buy a coat and some woolies.

I went skating yesterday and today. It is great fun, but hard. We skate on the frozen sewage farm. This has been the coldest November on record.

I expect I shall go into the Myoglobin program. Things are breaking out all over. We have 6 or 8 new crystal types, a couple of which are very good. Perhaps I shall try to determine molecular shape by the salt water method of Perutz.

Don't let Bob Corey get unhappy with JHS and a rotating anode tube. It would be a minimum of six months to have it made here, and it has been three years since Broad started to make it. I think you will get a better tube by letting Holmes do his damndest.

Having allowed myself to be wooed by an insane plan of a mad Rhodes scholar, I am leaving Wednesday for the Continent. We are supposedly starting for Vienna, but I am not sure we shall make it. Anyway, I expect an adventure of some sort. We shall probably do some skiing. Perhaps see Wasers. I shall advise an address if I know where we shall be.

Mamma, you are a darling girl. I have made inquiries for a coat, and should have one soon. I shall buy one in a couple of days. It will be very nice. I am going to get some long underwear tomorrow.

I had Thanksgiving dinner with some Americans named Campbell here. It was grand. Turkey, homemade bread, homemade cranberry sauce. I was very homesick. You were in the mountains at the same time.

I have bought a couple of minor gifts, but have not sent them. So I expect they will be late. I am sorry. Papa's gift has not arrived, it is on order. So it ought to be in time for birthday. I'll see what I can do.

Much love,

XXXXXX Peter

OOOOOO

DPR/MB 9th December 1952.

Professor Linus Pauling, Sc.D., Gates and Crellin Laboratories of Chemistry, California Institute of Technology, Pasadena 4, California, U.S.A.

Dear Pauling,

Thank you very much indeed for the useful information about punched cards and the Sherman-Cross strips. Now that I know exactly what is available, I am going in to the question of practicable computing procedures over here. We are less blessed with the latest I.B.M. machines than you. There is just a possibility of using an electronic digital computer and I am exploring this avenue first. So that, for the moment, I do not have to trouble you further with regard to the punched cards but I will certainly write again if it seems that I need them.

By the way, might I have reprints of your papers with Shaffer and Schomaker in J.Chem. Phys. 1946, 14, 648 and 659, if any are still available?

I am very glad to learn that you have now fixed a date for the Protein Conference. This ought to be a great success and I am eagerly looking forward to it. I shall certainly be able to come to it, but whether I shall be able to stay on afterwards will rather depend on developments here. The whole future of this Laboratory is now under discussion, including my place in it, and I shall have to await the results of these deliberations before

Professor Linus Pauling. -2- 9th December 1952.

knowing whether I can take up your very kind offer. Would it be possible for me to delay a decision about it until the Spring?

We have gone no further with the γ-helix or the 3-chain collagen model, except to satisfy ourselves that a large proportion of proline residues is incompatible with the former.

It is as well to have an independent check of our serum albumin curve. We are now working with increased resolution and intensity and have confirmed that poly - γ - methyl and poly -Y- benzyl glutamate have your α-helix structure.

With all best wishes,

yours sincerely,

D. P. Riley

A. Rich Linus Pauling 9 December 1952

Preparation of fibers of nucleic acid

I suggest that you try to make well oriented fibers of sodium thymonucleate or other nucleic acid preparations by the use of plasticizers.

The fact that 50 percent relative humidity seems to be required to give good fibers suggests that substances containing hydroxyl groups would be satisfactory plasticizers. I think that you should try adding a little glycerine to the solution. Perhaps ethylene glycol or diethylene glycol would be worth trying. In fact, perhaps all of these substances should be added to the same preparation - mixed plasticizers often are more effective than the individual plasticizers.

As to other substances, urea and salicylic acid and guanidinium ion might all be worth trying.

There is a possibility that dibutyl phthalate would be useful.

For one preparation you night try putting all of these things in the solution, with the nucleic acid, the plasticizers being added in rather small amounts.

I am also asking Dr. Marsh to make a spectrometer investigation, and to calculate a radial distribution function. Would you turn over to him about 0.5 g of a preparation, for this purpose. If your powder photograph of the sodium thymonucleate taken directly from the bottle gives as good a powder photograph as the recrystallized material, I suggest that you give him a sample of the material from the bottle. Small amounts of impurities would not be important.

Dictated by Linus Pauling

Signed in his absence:W

cc: Professor Corey L.P.

14 December 1952

My dearest Family

Now I am in Munich, in a youth lodging in Weidl. Picklock road, in West Mnchen. But I stay here density for a long time because my foreign in Vienna soon to get wants. But hopefully we will be here like you if we come back to England. Tomorrow go we to Linz and then to Vienna with the course. I came here with autostop. It is heavy I have it in not gladly more, but it is & cheaply. Thursday gangen we with the sdiffe after east end, and after Brussels with autostop. Friday after Aaden, and yesterday after Frankfurst. It necessarily is to come here again.

I become more selmyes and Sommerfeld now not more to behold, but if who zuriick kesmnen I will see her.

We become in Vienna velleicht one long week remains, lhi to know wrote me c/o America express, Vienna. A small letter. Thank you very much many times fiis everything. And the cash. I have now a Duffle Coat and a few wonderful shoes. With wool therein. My feet are warm estennal is England: I become a beautiful Rok soon Raufen.

This morning it snows much. The city is more, but it heavily to Salzburg will go very beautifully. Perhaps leisure we course take or. Buir remain. Frohlechste wine noting. I become to be there. I love you.

Peter

[Written in German]

Dec. 15

Dear Dr. Pauling

I have discovered three more satisfactory helices. In the notation of Bragg, Kendrew and Perutz, these are 3.0₁₀, 4.4₁₄, and 4.4₁₆. They have 2.00, 1.20 and 1.15 Å per residue along z. I suspect that 4.4₁₆ is the π of Barbara Low, but her description, unfortunately, fits both 4.4₁₄ and 4.4₁₆. 4.4₁₄ is somewhat strained (angle at α-carbon=102 degrees, and each residue is twisted 6 degrees [0.4 Kcal/mole/residue]), 4.4₁₆ is planar, but α-carbon angle is 114 degrees. This could probably be decreased a little. 3.0₁₀ is entirely satisfactory. I have written to Barbara for clarification, and when I get it, I am going to write these up, and will send you a copy before I submit it anywhere. I think it should be a letter to the editor of J.A.C.S.

I am also calculating radial distribution functions, in order to test the sensitivity of the method. I do not check your curves for the α-helix. Would it be possible for you to have a copy made of the list of interatomic distances (i.e., kind and length) so that I can see what went wrong?

I got another letter from Prof. Stanley in which he is rather more hopeful, but would rather talk things over with me personally. In as much as I should much prefer to locate in California rather than anywhere else, and since negotiations at this distance for any position are rather difficult, I am wondering if it would not be better for me to come back to Crellin for a year before taking a permanent place. You mentioned this possibility in one of our talks last spring, and I must confess it looks more attractive to me now than it did then.

Francis Crick's α-keratin letter appeared in the Nov. 22 Nature. it is now three issues later and yours is not out yet. I do not know any reason for the delay, but Francis is rather embarrassed by it, as he assumed the two letters would appear together. I believe that he is going to write you about it.

Arndt and Riley have found a 1.5 Å reflection in some oriented fibrous insulin which Freddie Gutfreund gave them. It will take some checking before they're sure, though. They have put all manner of proteins in their radial distribution machine, and are now chewing on the results. We hope to learn them shortly.

Merry Christmas

Jerry

I enclose a drawing of the 3.0₁₀, which I should like returned.

Dec. 16, 1952

Dear Dr. Pauling

I enclose copies of the radial distribution functions I spoke of in my last letter. For my curves with B=4, each interaction has the shape Z_iZ_j exp (-5r²) and for B=2, Z_iZ_j exp (-10r²) (as derived from the part in David Shoemaker's thesis on the shape of peaks in modified Pattersons. I calculated the distances to the closest 0.1 Å, and synthesized the curves at 0.1 Å intervals, up to 9 Å, since I feel interhelical distances may become too important beyond this. I used the coordinates on p. 240 of P.N.A.S. reprint set. Arndt has also recalculated R.D.I.'s for the α-helix, using likewise the 18-residue 5 turn coordinates. I enclose also a tracing of his curves. He used the function Z_iZ_j x the function: [table of data used in the function]

I include my two smoothing functions for comparison. I don't know what kind of smoothing function you and Dr. Corey used, but I don't see how a difference in them could lead to the big difference between your curves and mine and Arndt's.

Arndt now inverts the R.D.I.'s for the helix and compares scattering curves. He finds that for bovine serum albumin and egg albumin there is quite good agreement with the α-helix, and he still favors BC₂ over BC₁, or a 50-50 mixture is possibly the best of all. He has also calculated curves for α-helices of finite lengths, and thinks "in most of the globular proteins the agreement between model and experiment is best for a length of about 20 residues, the chains in α-keratin probably being longer." I have not yet talked to him about this last point, but the evidence for it cannot be very strong, for using a helix of finite length would merely depress the outer part of the curve gradually, I think. He writes also that he is now writing his work up and will go to press early in January.

I also enclose comparative R.D.I.'s for the α-helix, the 4₁₃ (not that I like it structurally, but I wanted to see what effect the extra twist had) and my 3.0₁₀, of which I sent you a drawing last week. I shall do the 4.4₁₄ and 4.4₁₆ as soon as I hear from Barbara about which is the π. (How does she put "π" between "α" and "γ", by the way?) She does not apparently realize that there are two kinds of helices, and that the α and γ are different kinds.

I'll send the data on the new helices (I have called the 3.0₁₀ the ζ-helix [?], as I discovered it before the 4.4₁₄ and 4.4₁₆. If Barbara is the 4.4₁₆, then the 4.4₁₄ remains to be lettered. It is not as satisfactory as the others, but perhaps it should be called ω, as I am now sure that there are no more, unless the condition of equivalent residues is abandoned). Incidentally, Carlisle still thinks the α-ribbon (2₇) explains ribonuclease! But he will not give coordinates of it. Understandably.

Sincerely

Jerry

19 December 1952

Prof. A. R. Todd

University of Cambridge

Cambridge

England

Dear Alex:

I was pleased to learn from the New York Times that you and your group have synthesized three coenzymes. I think that this is fine.

Dr. Corey and I are much disturbed that there has been no precise structure determination reported as yet for any nucleotide. We have decided that it is necessary that some of these structure determinations be made in our laboratory. I know that the Cavendish people are working in this field, but it is such a big field that it cannot be expected that they will do the whole job. On the other hand, we do not want to duplicate their investigations - it is more important that another nucleotide determination be made, in case that they carry out one of them. Probably I shall write to Bragg or Cochran pretty soon and ask which ones they are working on. If there is no objection on their part, we should like to ask you to provide us with material, if you have some crystalline preparations of nucleotides or related substances that you feel would be especially worth while investigating.

I may say that we probably shall try to determine the structure of some phosphate diester, perhaps not of the nucleotide class - information about the structure of phosphate diesters can be carried over directly to nucleic acid.

We feel strongly the necessity of having precise information about these substances because we have, we believe, discovered the structure of the nucleic acids. I think that it will be about a month before we send off a manuscript describing the structure, but I have practically no doubt about the correctness of the structure that we have discovered. I feel very grateful to you for having given me reliable information about nucleic acid, this summer. Our structure corresponds to the specifications that you laid down; in particular it involves 3', 5' linkages between the P-ribofuranose rings, by way of phosphate groups.

The structure is really a beautiful one. It is hard to describe without some drawings, which have not yet been made. I shall keep you informed.

I enclose a copy of a letter to Bragg, asking him for information that would keep us from duplicating work that is being done in his

Prof. Todd -2- 12/19/52

laboratory. I may say that we have been especially interested in leaking a structure determination of ATP. We have surmised that some unidentified crystals for which we have some x-ray data might in fact be ATP, but this has not yet been verified. If you have any preparation of a nucleotide that is in the form of crystals, even microcrystals, and could give us a small amount - enough to recrystallize into larger crystals - we should be happy to begin the investigation of it, provided that it does not interfere with your collaboration with the Cavendish group.

With best wishes to you all for Christmas and the New Year, I am

Cordially yours,

Linus Pauling:W

19 December 1952

Mr. Henry Allen Moe

John Simon Guggenheim Memorial Foundation

551 Fifth Avenue

New York 17, N.Y.

Dear Henry:

Thanks for sending me the clipping from the New York Times on the synthesis of some coenzymes by Todd.

Todd's work is of the greatest importance. I think that his earlier work on the synthesis of nucleosides and nucleotides is probably to be considered as more important than just the synthesis of these coenzymes. This recent synthesis is a continuation of the earlier work - an application of now synthetic methods that Todd discovered.

You no doubt remember that we had Todd over here, in the spring of 1938, and that we offered him a professorship. He would have accepted it, I think, except that the British got busy and arranged for a professorship at Manchester to be given to him. I believe that Todd is to be considered the leading organic chemist in Great Britain now, except for Sir Robert Robinson.

I talked with Todd about his work a good bit this summer; we stayed with the Todds in Cambridge. In particular, I discussed the significance of his results with respect to the structure of nucleic acids. Principally as a result of this meeting with him, I have now discovered, I believe, the structure of the nucleic acids themselves. Biologists probably consider that the problem of the structure of nucleic acid is fully as important as the structure of proteins. I think that Dr. Corey and I will probably send in a note on the discovery of the structure of nucleic acids next month; we want to check up on our present structure a bit more before announcing it.

Sincerely yours,

Linus Pauling: W

22 December 1952

Mr. Roger Hayward

920 Linda Vista

Pasadena 2, Calif.

Dear Roger:

Here is the information about the drawings that I need for the nucleic acid paper, in connection with the NFIP work.

The cylindrical coordinates for 20 atoms are given on the accompanying sheet. Here ρ is the radial distance from the axis of the cylinder (the axis of the helix), Ф is the azimuthal angle, and z is the coordinate in the direction of the axis. The coordinates are on a right-handed system, so that increasing z and increasing Ф generates a right-handed screw.

The first five coordinates, for P and four oxygen atoms, refer to the phosphate groups. The four oxygen atoms are at the corners of a tetrahedron, which is, however, not a regular tetrahedron. I think that so far as your drawings are concerned it would be satisfactory, however, to indicate the tetrahedron as a regular tetrahedron, without trying to take the relatively small distortions into consideration. The next three sets of coordinates for C_5', C_4', and C_3', represent three atoms which connect the upper right outer corner of an tetrahedron with the lower left outer corner of the tetrahedron that is in the layer above, and rotated 105° to the right.

I suggest that the first drawing indicate one helix, formed by one tetrahedron, the link to another tetrahedron in the layer above, that tetrahedron, the link to the tetrahedron in the layer above that, and so on. This helix is generated by taking the tetrahedron represented by the four oxygen atoms, the inner edge being formed by oxygen atoms with radius 2.00 A, and generating the next tetrahedron by translating the distance 3.40 A along the z axis and rotating through the angle 105°. This helical molecule executes seven turns in 24 tetrahedra. The pitch is 81.6 - that is, 24. x 3.40 A. I suggest that 24 - probably better 25 - tetrahedra be shown in outline, with arcs connecting them together, the arcs representing the atoms C_5', C_4', and C_3'. This would be just a diagrammatic representation. It might be worth while to show the axis of the molecule, as a straight line, and to draw a radius out from the axis to the center of the inner edge of each tetrahedron.

For the second figure, a representation of the three-chain structure should be drawn. This can consist of 25 tetrahedra and the connecting

Mr. Hayward 22/12/52

arcs, as in the first figure, and the same repeated after rotation through 120° and 240°. The molecule consists of three helical chains that are related to one another by the operations of a three-fold axis.

It would be good also to have a perspective drawing showing all 20 atoms, plus five more - the phosphate group to which the first phosphate group is connected by the chain of atoms C_5', C_4', and C_3'. In this drawing bonds should be shown connecting the atoms. The phosphorus atom is bonded to the four oxygen atoms that constitute the tetrahedron about it. Then O_III is bonded to C5'. The other bonds are C_5'-C_4', C_4'-C_3', C_3'-C_2', C_2'-C_1', C_1'-O_1', O_1'-C_4' (forming a five-membered ring), C_2'-O_2', C_1'-N₃, N₃-C₄, C₄-C₅, C₅-C₆, C₆-N₆, C₆-N₁, N₁-C₂, C₂-O₂, C₂-N₃. The other five atoms to be shown, the other phosphate tetrahedron, are obtained from the coordinate for the phosphorus and the surrounding four oxygen atoms by increasing z by 3.40 A and increasing by 105°. I think that it would be wise in this figure to show the helical axis, and perhaps the radii from the axis to the centers of the inner edges of the two tetrahedra.

Please telephone me if there is any question in your mind about the nature of this structure, or if you think that I have made some mistake in this description.

Sincerely yours,

Linus Pauling: W

22 December 1952

4, Pfeilgasse

Wien VIII

Dearest Parents,

Two days until your birthday, three days until Christmas. Tonight at midnight we leave by train for Eisenerz, in South Austria. My friend Mike Bennett has some friends there and we shall spend Christmas there. I hope it will be nice. The only way not to be unhappy is not to think.

We have been hitchhiking. Sort of rough, but not bad. An immense amount of snow in the Bavaria. Very, very beautiful. I must to go Garmisch. Probably not this year, but next. I am sort of in favour of returning to England the way we came, through Germany, and spend time in each city.

We arrived in Vienna a week ago late tonight. I have seen Die Hochjeit des Figaroes, Wiener Biut, Die Zauberflte, Don Giovani, Das Christelflein by Ilse Staeh and Hans Pfitznen, and two concerts by the Wiener Philharmoniker. I got most out of and enjoyed most Don Giovani of the operas. It is difficult to tell what is going on. I bought the texts and it is fun. Yesterday I heard a Beethoven concert in honor of his birth. A really superb performance. Rondino, E flat major, Oete & for winds, with Hans Kamesch, Karl Swoboda, Leopold Wlach, Fran Bartosek, Otto Schieder etc. And a wonderful fifth symphony. I like music more than opera.

Before leaving I bought some lovely lambs wool lined boots, really nice, and they keep my feet nice and warm. I hope to wear them for years here. And some long underwear and a duffle coat. It is heavy, but warm , and suitable for a roughing trip like this.

I live in a student house. Ninth floor. Special price Twenty cents a day.

Prices are about twice what they were two years ago. Wurst and cheese about 50 a pound. Tram 5. I think, though these Continental countries have all sorts of good things in store windows, They are not as well off as England, as far as most people go.

Could you please send me more or less accurate design drawings of those wire swimming pool chairs? Material diameter, lengths, bend angles, and radii of bends. I want to make a couple, and I shall send for covers through you when I get them the chairs. Also, M. Milne would like an address where to order them. Could you please tell me? I think it would be cheaper and easier to make them or have them made here.

Three shopping days left. And I have bought no presents, much less mailed them. Sent some toys to Linus Jr. A little broom to Petie. Damn.

It is certainly grand here. Hitchhiking is not really bad and is quite cheap. I can say this now. After a couple of hours in the snow it is not quite the same.

Happy birthday, darling Mamma. And Merry Christmas Daddy, Mamma, Linda, and Crellin.

I love you,

Peter

23 December 1952

Dr. Jerry Donohue

Cavendish Laboratory

Free School Lane

Cambridge, England

Dear Jerry:

I am interested to learn about the helixes that you have been working on.

As to the helix 3.0₁₀, this is the one that is described in our paper with Branson, as corresponding to the rotational angle 120° (which gives 3.0 residues per turn), end as having the same orientation as the α helix. Dr. Branson concluded from his very complicated analytical treatment that the hydrogen bonds are badly bent. Also, the crude model that he made indicated similar bad bending, although our new models show that the strain in the hydrogen bond is small - there is a bending by about 40° at the oxygen atom, which, however, is of course allowed. Our van der Waals models indicate that the helix is too tight, introducing steric hindrance along the axis, but of course van der Waals radii are not very reliable. Also, I am reasonably sure that this is the structure that Huggins discussed, as having three residues per turn; it is, I think, the one that he thought, at the time of the New York meeting in the fall of 1951, to be the α helix. He did not discuss the α helix.

I am sure that the helix 4.4₁₆ the one that Barbara low has described. We had made an investigation of it, and some months ago I asked Dr. Yakel to calculate its radial distribution function, using the helicometer. I do not think that he has yet made this calculation - he decided to rebuild the helicometer, and has put it into operation only recently. In our considerations about 4.4₁₆, carried out before we know it was Barbara Low's structure, we decided that the strain should be relieved mainly by twisting the amide group from the planar configuration, rather than increasing the α -carbon angle. Probably the strain is relieved partially in each of these places.

We have not made any study of 4.4₁₄, which is like the gamma helix, but twisted more tightly. (The series of α helices has subscript 3n+4, and the series of gamma helixes has subscript 3n+5.) The amount of strain is so great - you say 7° on the α -carbon angle and 6° twist of the amide group - that this configuration should, we think, be ruled out. I think, although I am not sure, that it is mentioned under the angle 108° in our table - this corresponds to 3.3₁₄, but we were putting all of the strain into the hydrogen bonds. Perhaps 108° represents 3.3₁₁, with 3.3₁₄ left out because of its deviation from our assumed structural features.

Dr. Donahue Page 2 23/12/52

As to your publishing a description or discussion of these, I would say that it might be well worth while for a complete discussion to be published, about all of the α helixes (N_3n+4) and all of the gamma helixes (N_3n+5). I would say that an effort should be made to find the best configuration for each of these, dividing the strain among the different structural features in the way that minimizes the strain energy. In my paper for the Ninth Solvay Congress, which should be available soon (Bragg will have a copy, probably in about one month, or I can send you part of the manuscript), I give energy expressions for stretching and bending covalent bonds, twisting the amide group (the same expression as before), van der Waals interactions - at any rate van der Waals attraction. I think that it is van der Waals repulsion, steric hindrance, that might be the hardest to take into consideration. I would say that the time has passed now for piece-meal discussion of these structures. Of the three that you mention, 4.4₁₄, which is probably the worst of the group, is the only one that has [sic]

I doubt that a discussion of these three structures is worth a letter to the J.A.C.S. - that is, I think that a more detailed discussion should be published, at sometime, rather than a letter. Since so much discussion of polypeptide chains has been published in the Proceedings of the National Academy of Sciences, I suggest that you consider submitting a paper there, that is, sending the manuscript to be submitted to the Proceedings. Your paper could be up to six printed pages long. Why don't you consider expanding it, to include all of the α helices that are at all reasonable, and all of the gamma helixes that are at all reasonable?

I think that it would be fine for you to publish radial distribution curves, in each case with two alternative positions for the β carbon atom, unless one is clearly ruled out by steric hindrance, as it seems to be for 3.0₁₀.

Filey has pointed out that our radial distribution curves for the α helix are not very accurate. I haven't tracked down the error, but I think that we may have smoothed the points out a bit too much. You might check with Riley and Arndt, rather than with us, to see whether you get agreement for the α helix.

Dr. Corey and I have been rather disturbed by the delay in publishing our communication to Nature about the structure of the α -keratin proteins. I wrote to the editors of Nature on 2 October, saying that we were anxious to have our manuscript published quickly, and asking if Nature would be interested. The editors replied at once that they would be, and we submitted the manuscript on 14 October, eight days before Crick's manuscript was submitted. I have now written the editors asking what has gone wrong, and saying that it seems to me that editorial policy should have led to the publication of the two communications in the same issue of Nature, or that, at any rate, the one that was submitted earlier should not be published at a considerably later tine. Dr. Corey and I are hoping that ours will not be delayed so long that it will have a 1953 date.

Dr. Donahue Page 3 23/12/52

As to your idea of coming back here, in order to increase the chance of your getting a permanent appointment in California, I think that it can be arranged. Dr. Corey and I are embarking on a new project, the determination of the structure of nucleic acids and nucleoproteins. We hope to have a short paper on the structure of nucleic acids published within two months - we are not going to send it to Nature. In connection with this work, we want to have some precise structure determinations made of phosphate diesters, nucleosides, nucleotides, and so on. I have written to Bragg about this matter, in order that we shall not be making structure determinations on the same substances as are under investigation in the Cavendish. We have not yet got a grant for increasing this activity next year, but I think that we shall get it, and we should know within two or three months. As soon as we hear, we can make a definite offer of appointment to you, as Senior Research Fellow in Chemistry, at salary fit the rate of $5400 per year, with the obligation of working on the structure of these substances.

With best regards, I am

Sincerely yours,

Linus Pauling:W

P.S. I return your drawing herewith. LP

24 December 1952

Eisenerz, Austria

Dear Mamma,

Happy birthday & hope you are having a good time.

Here we are. We took a train Monday at 234d & rode all night to Leoban. This town of 11000 people is 20 miles north of Leoban, in Southern Austria. It mines iron almost completely and is in a valley surrounded by beautiful mountains. We had a glorious trip in a big mail truck from Leoban, through snow and mountains. There is snow everywhere, everything is covered, and there are forests of Christmas trees all snow covered. It is like our trip in Switzerland, only more snow, less majestic mountains, and more trees.

We are staying with the Director of this iron company. We are really in a gashouse belonging to the company, because relatives are coming for Christmas, and we go all the time to the house. The boy is about 27, the girl 21, and they have just come back from the United States. The Mother is very nice, I like her. I do not know how long we shall stay here, but probably a week. I was going to have long hair but they wanted me to have it cut, so I did. It is now very nice, not as short as German crewcuts, but just right. All Austrian men have hair cuts for Christmas.

It was very nice in Vienna. I like it there very much. In another couple of years.

I look out the window to the lovely white mountains. It is grand. Considering the possibilities, Christmas and your birthday could hardly have been spent in a more nice place. Considering impossibilities, I can think of places where I would much prefer to be. Sometimes it is sad to grow up.

Happy birthday and merry christmas.

I love you

Peter

31 December 1952

Professor J. T. Randall, F.R.S

King's College

University of London

Strand, W. C. 2

London, England

Dear Randall:

I am pleased to have your letter of 23 December, and to learn about the meeting on the Nature and Structure of Connective Tissues, that you are organizing for 26 and 27 March.

I am not sure at the present time whether any of the members of our staff will be able to attend the meeting. I myself am planning to come to Europe for the Ninth Solvay Congress, 8-14 April. This trip, however, requires me to be absent from the California Institute of Technology during term time, and I am accordingly planning to make it as short a trip as possible. It seems unlikely that I shall be able to leave Pasadena nearly two weeks earlier than would otherwise be necessary, in order to participate in your nesting, although, of course, I am very much interested in the subject.

Professor Corey and I are especially happy during this holiday season. We have been attacking the problem of the structure of nucleic acid during recent months, and have discovered a structure which we think may be the structure of the nucleic acids - that is, we feel that the nucleic acid molecule may have one and only one stable structure. Our first paper on this subject has been submitted for publication. I regret to say that our x-ray photographs of sodium thymonucleate are not especially good; I have never seen the photographs made in your laboratory, but I understand that they are much better than those of Astbury and Bell, whereas ours are inferior to Astbury and Bell's. We are hoping to obtain better photographs, but fortunately the photographs that we have are good enough to permit the derivation of our structure.

Sincerely yours,

Linus Pauling:W