PROCEEDINGS OF THE IRE

Twelfth General Assembly of InternationalScientific Radio Union *FREDERIC H. DICKSONt, MEMBER, IRE

n VERY three years, the International ScientificRadio Union holds a major international meet-ing, or General Assembly, which is attended by

leading radio scientists from all over the world. Lastyear URSI held its Twelfth General Assembly atBoulder, Colo. from August 22 to September 5. Thiswas only the second time in 30 years that the UnitedStates has had the honor of being host to this importantgathering.

Miore than 500 distinguished radio scientists andtheir families from twenty-six countries attended at theinvitation of the U.S.A. National Committee of URSIand the National Academy of Sciences. The meetinggave the participants an excellent opportunity to ex-

change technical information, coordinate research pro-

grams on an international basis, and make recommenda-tions concerning future courses of scientific action.The United States preparation for this assembly was

the responsibility of Dr. J. Howard Dellinger, formerChief of the National Bureau of Standards RadioPropagation Laboratory, and now an Honorary Presi-dent of URSI, as Chairman of the General Arrange-ments Committee. Dr. Dellinger had many able assist-ants, too numerous to credit individually, who formedthe finance, foreign arrangements, technical, and localarrangements subcommittees.At the suggestion of Dr. Dellinger, several reports

summarizing the principal discussions of the seven URSICommissions during the Twelfth General Assemblyhave been prepared especially for this issue of PROCEED-INGS, and appear in the following pages. These reportshave been prepared either by the U.S.A. CommissionChairmen or by a U. S. reporter of that Commission.The reports are preceded by a brief description of theURSI organization by the chairman of the U. S.National Committee, and the welcoming address pre-

sented to the assembly by the President of the NationalAcademy of Sciences.

*Original manuscript received by the IRE, April 17, 1958.t Coordinator, URSI-IRE Reports; Chief, Signal Corps Radio

Propagation Agency, Fort Monmouth, N. J.

The following condensed program will indicate thewide scope of subject matter covered in the technicalprogram of the assembly; its high points are summarizedin the reports that follow.

SESSIONS OF THE COMMISSIONS

Commission I-Radio Measurement Methods and Stand-ards

August 26-Business and miscellaneous.August 28-Frequency standards (particularly

atomic standards).August 29-Standard frequency and time signal

transmissions.August 30-Power and field intensity measurement.September 2-Atomic frequency standards and stand-

ard frequency transmissions.September 3-Physical measurements based on radio

techniques (velocity of light, etc.).September 4 Concluding session (resolutions, etc.).

Commission II-Tropospheric Radio PropagationAugust 26-Business and miscellaneous.August 28-Tropospheric propagation within the

horizon.August 29-Tropospheric propagation beyond the

horizon.

August 30-Radio meteorology.September 2-Tropospheric scattering.September 2-CCIR matters, resolutions.September 3-Additional discussion of tropospheric

scatter propagation, and other un-

finished business.September 4-Concluding session (resolutions, etc.).

Commission III-Ionospheric Radio PropagationAugustAugustAugust

August

26-The opening business meeting.28-The lower ionosphere.28-Geomagnetic influences in the iono-

sphere.29-Whistlers, etc. (joint session with Com-

missions IV and V).

We are privileged to present in the following pages a series of reports covering themajor activities of the Twelfth General Assembly of the International Scientific RadioUnion held in Boulder, Colo. last summer.

The material was prepared especially for this issue by officials of the seven U. S.Commissions of URSI, under the coordinating guidance of Frederic H. Dickson, inter-national Vice-Chairman of Commission IV and member of the U. S. National Com-mittee of URSI.-The Editor.

1350 Jul/y

Wells: What Is URSI?

August 29-Geomagnetic storms.August 30-Horizontal movements in the iono-

sphere.September 2-Scattering in the ionosphere.September 2-Business session on urgent matters.

1) Consideration of a proposal toestablish a permanent center forionograms.

2) Collaboration of Commission IIIin connection with CCIR topics.

September 2-The events of February 23, 1956.September 3-Rocket exploration of the ionosphere.September 4-Closing business session.

Commission IV-Radio Noise of Terrestrial OriginAugust 26-Business session, report of working

groups.August 28-Whistlers and other vlf phenomena.August 29-Whistlers, etc. (joint session with Com-

missions III and V).August 30-Characteristics of radio noise.August 30-The measurement and description of

the characteristics of atmospheric noise.September 2-Commission IV activities during the

IGY.September 3-Relation between source and atmos-

pheric.September 3-Business (resolutions).September 4-Resolutions and final business.

Commission V-Radio AstronomyAugust 26-Business and miscellaneous.August 28-Techniques of reception.August 28-Large antennas.August 29-Solar research.August 30-Radio sources.

August 30-Radio propagation, joint session withCommission VI.

September 2-The galaxy.September 3-Planetary system.Joint sessions as follows:August 28-Commission VI on large antennas.August 29-Commissions III and IV on whistlers,

etc.September 3-Commission VII on masers.September 4-Business session.

Commission VI-Radio Waves and CircuitsAugust 26-Business; microwave optics and infor-

mation theory.August 28-Circuit theory.August 28-Large antennas (joint session with

Commission V).August 29-Information theory.August 29-Transition from field theory to circuit

theory and optics.August 30-Information theory.August 30-Scattering and diffraction.September 2-Circuit theory.September 2-Surface waves.September 4-Business session.

Commission VII-Radio ElectronicsAugust 26-Business session.August 29-Oscillation phenomena in gas dis-

charges.August 30-Physics of the cathode.September 2-Source and nature of noise in electron

beams.September 3-Physics of semiconducting devices.September 3-Molecular amplifiers (masers).September 4-Second business session.

What Is URSI?*H. W. WELLSt, FELLOW, IRE

TvHE Twelfth General Assembly of URSI washeld in Boulder, Colo., August 22-September 5,1957. Several hundred foreign delegates and a

like number of U. S. representatives participated inthe meetings. The General Assemblies, now held everythree years, had met only once before (1927) in theUnited States. Excellent facilities were provided for

* Original manuscript received by the IRE, April 17, 1958.t Chairman, U. S. A. National Committee, URSI; Dept. of Terr.

Magnetism, Carnegie Institution, Washington 15, D. C.

this meeting by the University of Colorado and theNational Bureau of Standards, Boulder Laboratories.Besides the technical sessions there were numerousexcursions and entertainments. The foreign delegateswere given a vivid portrayal of the peace and beauty ofwestern United States. The meeting was pervadedwith a remarkable spirit of solidarity and satisfaction.The following international officers were elected for theensuing three years:

19-58 1351