UNIVERSITY OF LONDON KING'S COLLEGE.

From The Wheatstone Professor of Physlcs,

J. T. RANDALL, F.R.S.

STRAND, W.C. 2.

TEMPLE BAR 5661

(6 hiuse).

DP, Re FranXLh,

12 quai Henri IVY
Paris IV,

4th December, 1950

Dear Dr. FranlCLIn,

I am sorry I have taken so long to reply to your letter of November

24th. The real difficulty has been that the X-ray work here is in a
somewhat fluid state and the slant on the research has changed rather
since you were last yere.

After very careful consideration and discussion with the senior

people concerned, it now seems that it would be a good deal more
important for you to investigate the structure of certain biological
fibres in which we are interested, both by low and high angle
diffraction, rather than to continue with the original project of work
on solutions as the major one,

Dr, Stokes,, as L have long infarlzed, really Mishes to concern

                                           It will

himself almost entirely with theoretical problems  in the future and
these will not necessarily be- confined to X-ray optics.
probably involve microscopy in general, This means that as far as the
experimental X-ray effort is concerned there will be at the moment
only yourself and Gosling, together with the temporary assistance  of a
graduate from Syracuse, X'Irs, Heller, Gosling, working in corljunction
with Eilkins , has already found that fibres of desoxyribose nucleic
acid derived from mterial provided by Professor Signer of Bern gives
remarkably good fibre diagrams,  The fibres are strongly negatively
birefringent and become positive on stretching, and are reversible
in a moist atmosphere.
extremely important constituent of cells and it seem to us that it
would be very valuable if this could be followed up in detail, IT
you are agreeable to this change of plan it would seem that there is
no necessity immec?5at;ely to design a camera for work on solutions,
The camera will, however, be extremely valuable in searching for large
spacings from such fibres,

As you no doubt ,2mow, nucleic acid is an

  I hope you will understand that I am not in this way suggesting that
we should give up all thought of work on solutions, but we do feel that
tire work on fibres would be more immediately prof itable and, perhaps ,
f undamnt a1 .

i think I mst leave to you the question as to whether you come  over
here for a day or two to discuss these matters further, It now seems
so near to the time Wheri you will actually be working here that  it is

perhap hapdl necessary for you to make the special journey, On

apparatus side in Paris and you could hardly do this without further
discussion with us. The change of program, such as I have 4
suggested, will probawy mean that we should obtain the formal
consent of the Be@,LcWshLjj Cormittee; there is no hurry about this
and there is no doubt about the answer.

the other han % *'%here may be things which you could organize on the

Dr. Frice has just heard from Mr. Heins of the -Rockefeller

Foundation that orders have now been placed for your apparatus,

Yours sincerely ,

mil4.+&&