Theodore R. (Ted) Madden has been instructing students and assisting colleagues in the science and art of exploration geophysics for more than thirty-five years. During this same period of time, he has supervised and completed a substantial amount of research into the geophysical exploration methods that interest him the most. Since Ted's mind is always racing on to a new project before the last one is complete, not all of this original work has found its way into print. Fortunately, we can gain some insight into the scope of Ted's contributions to our science through the theses and publications of some former students and co-workers.
     After three years in the U.S. Navy in 1946, Ted began his long association with the Massachusetts Institute of Technology. He received his B.Sc. Degree in 1949, after working summers with the group at Woods Hole.
     He began his graduate career at MIT in 1950, and began to instruct and assist his fellow graduate students almost immediately. He had been functioning as a professor of geophysics for many years before he received his Ph.D. in 1961. Throughout this period, and in the years since, Ted has worked in association with, and taught many of the exploration geophysicists who have been responsible for pushing back the frontiers in the use of geophysics in the search for petroleum and mineral deposits. It is typical of Ted Madden's relationship with these well-known and successful scientists, that each of them will freely acknowledge the benefits that they realized from their association with him.
     Although the Honors and Awards Committee has stated that the Reginald Fessenden Award for 1986 is being awarded to Professor T. R. Madden in recognition of his "pioneering efforts in the development of frequency domain IP, both in practice and in theory," he has served with distinction as an educator whose many former students have written commendations of his insight and understanding of electrical phenomena.
     Ted's work with the variable frequency induced polarization method was only the first of his many efforts in the general field of electrical methods in geophysical exploration. In recent years his major research has been into the nature of magnetotelluric fields, and their use in petroleum exploration.

     There is not space enough in this short citation to list the many subjects in which Ted Madden has made a major contribution. However, I would like to close by mentioning one product of Ted's great intuition into electrical methods.
     In the summer of 1954, we were in a small Canadian exploration camp, experimenting with what was later to become the variable frequency induced polarization method. For some time we had been plotting the induced polarization and resistivity values we measured as either profiles for constant electrode separation or as a function of the varying electrode separation, used to make the measurement. Neither procedure was very satisfactory, if the earth geometry encountered was not that of the approximately horizontally layered earth found in petroleum exploration.
     In a few evenings of "doodling," Ted developed the two-dimensional, pseudosection plotting array that permits the geophysicist to separate lateral variations in the earth's electrical parameters from vertical variations in these same parameters. The first such pseudosection was plotted using data measured over the South Ore Zone at the Mindamar Mine on Cape Breton Island.
     Since that time, many thousands of line miles of IP and resistivity data have been plotted using the pseudosection technique. Today, a large percentage of this type of data measured in the world is plotted in pseudosection form. The pseudosection format
     was not a major scientific breakthrough, nor was it the result of profound scientific analysis. It was rather a result of the intuitive grasp that Professor T. R. Madden has always shown toward the use of electrical methods in exploration geophysics and
     also in the teaching and practice of that subject.
     It is for this reason, as much as any other that I feel Ted Madden richly deserves the award that the Society is bestowing upon him. I'm certain that his many former students and his past co-workers applaud his honor, as I do. I'm very proud to have been associated with the event.

     Philip G. Hallof