November 16, 1945
Dr. W.A. Noyes, Jr.
National Defense Research Committee
1530 P Street, NW
Reference: Your No. 10-151, OEMsr-103
13 October, 1945
Dear Dr. Noyes:
Listed below with mention of their respective contributions are the personnel
who are employed under Contract OEMsr-103, and Supplement No. 1 thereto, entitled
"Development of an instrument for the rapid determination of particle-size distribution
1. Professor Linus Pauling, Official Investigator throughout the life of the
contract, was asked by Dr. J.B. Conant in a letter dated June 13, 1941, to give his
attention to the "old problem of measurement of particle size and particle-size distribution,
.... particularly along the lines of portable instruments which might be developed
for the particular purpose of testing smoke clouds." Professor Pauling relied on June
18, 1941 by proposing the type of instrument which became the subject of Contract
OEMsr-103. The subsequent work followed closely along the path outlined in this original
2. Professor J.H. Sturdivant was responsible for the supervision of the experimental
work and the detailed design of the instrument throughout the period of the contract.
3. Mr. William N. Lipscomb, Jr., employed from June 7, 1942 to June 30, 1943,
contributed greatly to the development of the instrument. He produced multidisperse,
stable smokes for testing the instrument, compared several arrangements for charging
the particles, investigated with the electron microscope the separation of particle
sizes by the instrument, and examined the precipitation process mathematically.
4. Dr. Thor R. Rubin, employed from February 23 to September 30, 1942, studied
unidisperse smokes for testing the instrument, assembled and put into operation the
first instrument, and improved the airflow through it to obtain a steady pencil of
5. Dr. Eugene H.Eyster, employed October 1 to December 31, 1941, searched the
literature, uncovered the parallel experiments of Rohmann, and prepared a vacuum-tube
electrometer for use in the instrument.
6. Dr. Austin L. Wahrhaftig, employed December 1, 1941 to February 28, 1942,
constructed the power supply for charging and deflecting the smoke stream.
7. Dr. Charles D. Wagner, employed August 20 to September 20, 1941, assisted
in preliminary measurements.
8. Mr. George Standart, employed part time between November, 1942, and May, 1943,
assisted Mr. Lipscomb.
The work of Contract OEMsr-103 covered the design and investigation of an instrument
in which the particles in a smoke stream could be charged electrically and precipitated
on a collector at positions correlated with the sizes of the particles. A theoretical
analysis showed that the function relating locus of precipitation to particle size
is double-valued; the distribution is turned back upon itself in such a way that the
smallest particles precipitate with the largest. The agreement between theory and
experiment is fairly good, but the range of sizes of the particles precipitated at
a given point is rather large. It was concluded that possible the precipitation apparatus
could be developed into a usable laboratory instrument, but that it could hardly be
perfected for field use.
I hope that this letter provides the information you desire for the history of
Division 10 activities. Please let me know if further details on OEMsr-103 are needed.