Copy of report filed under "PROGRESS OF RESEARCH REPORTS"
April 5, 1939
Dr. Irvin Stewart, Director
Committee on Scientific Aids to Learning
41 East 42nd Street
New York, New York
During the past few months the situation with respect to the Fourier Calculator which
we hope to construct has changed greatly. The plans initially made for a Fourier
Synthesizer of rather conventional design were unsatisfactory, as pointed out by Dr.
About two months ago Dr. C. A. Beevers, of Liverpool, wrote to us suggesting that
a Fourier Calculator could be designed for crystal structure use along the lines of
the Beevers-Lipson strips, which are now being used successfully here and in other
laboratories. Mr. Philip A. Shaffer has acted on this suggestion and has made a preliminary
design of a Fourier Calculator of the new type, described on the accompanying pages.
This calculator seems to be extremely promising. We had estimated that a two-dimensional
Fourier synthesis, which now requires from four days to a week for its calculation
with use of the Beevers-Lipson strips, could be carried out with a harmonic synthesizer
drawing curves in from twelve to sixteen hours. The new Fourier Calculator would,
it is estimated, turn out the same job in from one to two hours, an improvement over
present methods by a factor of about 50. This improvement in the crystal structure
technique should be of extremely great value, permitting an attack to be made on crystals
of highly complex structure, such as those of proteins and other substances of biological
Since Mr. Shaffer has not had experience in instrument design, we have made arrangements
with the Observatory Council of California Institute for an expert instrument designer,
Mr. Michael Karelits, to devote part of his time to the detailed design of the Fourier
Calculator this Spring.
Mr. Karelitz is employed permanently as an instrument designer in connection with
the construction of instruments for use with the 200 inch telescope at Mt. Palomar.
I believe that we can be sure that a satisfactory detailed design of the instrument
will be prepared under Mr. Karelitz's direction. The designing process is now well
under way, and we expect the design to be completed within two months.
I should like very much to have the construction of the Fourier Calculator begun immediately
on completion of the design and completed if possible during the summer. Mr. Karelitz
estimates that the cost of construction will be about $2000, aside from the cost of
the design. From previous experience with the construction of apparatus, I would
expect that the machine might accordingly cost between $2000 and $2500. Our research
funds permit us to bear the cost of the design and a portion of the cost of construction,
but not the entire cost.
I accordingly apply to your Committee for a grant of $2000 to be used for the construction
of a Fourier Calculator for use in connection with the determination of the structure
of crystals by x-ray methods.
I wish again to point out that this calculator would be used very extensively. There
are in these Laboratories at present three staff members (Pauling, Sturdivant, Helmholz),
four post-Ph.D. fellows (Corey, Hughes, Levy, Weinbaum), and several graduate students
devoting their research efforts largely to crystal structure work.