The SEG's most prestigious award, election to honorary membership, has been conferred upon only 17 persons in the 32 years that the Society has been in existence. All of them were elected in appreciation of their outstanding contributions to geophysics, but if we review their histories we find that nearly all of them qualified for this recognition in one of three ways. Some advanced the field significantly through technical contributions, others through their accomplishments in furthering geophysical education, and still others through long and distinguished service to the SEG itself.
     This year, the Society has elected a pioneer in exploration geophysics, Dr. Sigmund I. Hammer, to honorary membership in recognition of the important contributions he has made not in just one but in all three of these directions. Best known for his technical accomplishments in the field of gravity interpretations, he has taught geophysics at a leading university for sixteen years, and has served the SEG with distinction in a great many capacities, including its presidency.
     Dr. Hammer began his career in geophysics early in 1929 after receiving his Ph.D. from the University of Minnesota. Joining the staff of the Gulf Research Laboratories, now the Gulf Research and Development Company, he was assigned to work in a group led by Dr. E. A. Eckhardt which was carrying out research in oil exploration by gravity and magnetic methods. His first task was to develop formulas for interpreting torsion balance data. These formulas must have worked very well because the first location the group recommended on torsion balance indications turned out to be the discovery well for the Hankamer Oil Field in Liberty County, Texas.
     As the pendulum and then the gravimeter came into use at Gulf, Dr. Hammer played a leading part in developing new interpretation techniques for handling their readings. In 1946, he became Dr. Nettleton's successor as head of the Gravity Interpretation Section of G.R. & D.C., a position he still holds.
     Thanks to a liberal publication policy on Gulf's part, many of Dr. Hammer's technical contributions have been published and are still widely referred to throughout the profession. His terrain correction templates and tables have become standard tools wherever gravity is used in exploration. His expression for determining the mass of an ore body from its gravity anomaly has been especially important to mining geophysicists. To illustrate the range of his interests, literally as well as figuratively, he has published a paper on gravity effects in several sky scrapers and also one on gravity deep in a mine shaft. During his survey of the Chrysler Building he discovered by gravity alone that a floor is missing in the Building, a secret previously known only to its builders.
     Since 1946, Dr. Hammer has taught a course in geophysical prospecting at the University of Pittsburgh and has had a total of 500 students in his classes during this period. His educational activities have not been confined to the classroom as he has prepared several valuable review-type papers on gravity and magnetic prospecting. An outstanding invited paper of this type was presented in 1955 to the World Petroleum Congress in Rome.
     For more than 20 years, Dr. Hammer has been active in the SEG and other scientific societies and has served them in many constructive ways. He was elected Vice-President of the SEG in 1950 and President in 1951.
     After serving as President, he succeeded Dr. Eckhardt as Chairman of the Geophysical Activity Committee, holding this position for three years.
     From this brief summary of Dr. Hammer's contributions it should be clear that the Society, in conferring honorary membership on him, is giving highly deserved recognition to a distinguished record of accomplishment and service in geophysics extending over a third of a century. Thanks to him and a few other leaders whose contributions have benefited the profession as a whole, our field has maintained its vitality and added to its stature in the world of science despite recurrent recessions in activity and other economic hardships. We cannot properly discharge the debt we all owe to this small group but through such means as honorary memberships we can convey recognition and express appreciation. It is now my great pleasure, Dr. Hammer, to present you with this plaque on behalf of the Society with our best wishes for your next third-century of achievement in geophysics.

     Milton B. Dobrin

     Response by Sigmund I. Hammer

     I appreciate, more than I can say, the eloquent and un-merited citation by my long-time friend Dr. Dobrin. This is a great moment for me, and I am at a loss for words to express adequately my profound feelings of gratitude to all my friends and colleagues in SEG.
     As I look back over the 33 years I have worked in geophysics, I can only think how much fun it has been. I have had the rare pleasure and privilege to see and be a part of the great developments of geophysical exploration in the span of a single lifetime. This is a rare and spectacular thing in the whole history of science and engineering. I have enjoyed every minute (well almost every minute) of it. Geophysics is my hobby as well as my work. You have chosen to honor me for simply doing what has always given me the greatest pleasure.
     Like most of the older people in this room, I didn't start out to be a geophysicist. My education was in physics. My Ph.D. thesis was on atomic collisions. But the problems I have encountered in geophysics have never failed to test all my training and abilities to the utmost. I had no difficulty shifting my interests from problems in pure physics to equally exciting problems in geophysics. And may I point out that interdisciplinary professions are even more fashionable today than they were several decades ago when I entered "geo-physics."
     But we have only started. Geophysics as a profession is relatively young. The opportunities ahead are greater than ever. As I now stand at the apex of my career in geophysics, I congratulate all you younger people, men and women, for the wonderful experiences of discovery in geophysics that you surely will have in the years ahead. I can only hope that many of you will derive as much pleasure from your work in geophysics as I have.
     This moment will always stand in my memory as the highlight of my professional career in geophysics. Also, I can never forget the many wonderful friends I have met and worked with in the SEG. It has been an honor and a pleasure to work with you. Thank you all from the bottom of my heart.

     Sigmund I. Hammer