Radio Broadcast (May-Oct 1925)

452 Radio Broadcast tainment that a full program affords, or you might, like Professor Hazeltine, answer that it is the science of radio which interests you. Professor Hazeltine explains that it was the opportunity to work out mathematical problems that first led him to experiment with radio. He has never been especially interested in either the programs of broadcasting stations or in attempts to receive long distances. He has been concerned with little but the scientific side of wireless. It is characteristic of the man that he did not have a neutrodyne set himself until several years after he had worked out the fundamental theory mathematically and had made application for his patents. PROFESSOR HAZELTINE LIKES MATHEMATICS MATHEMATICS has always been a favorite of mine," he says. "At school I once received a prize for my good work and my highest grades were always in mathematics. By chance, I graduated first in my class, but that was only by chance, for I had consistently held second place until the leader went to live in another city. From a high school in New London, Connecticut, I transferred to Stevens Institute of Technology where in 1906 I graduated with the degree of Mechanical Engineer." Professor Hazeltine is too modest to tell that he finished his school and college course in twelve years instead of the sixteen most of us give to it. He prefers to let people find that out for themselves. "I remember," he reminisces, "when I was a little boy I saw my uncle working out some algebraic calculations: he explained that he made those queer hieroglyphics just for amusement. I marvelled at such a pastime when there were such sports as baseball and swimming to claim spare hours. I had no premonition that some day I, too, would devote my leisure to the same queer hieroglyphics. "When I entered Stevens Institute I did not know what branch of engineering I wanted to take up, but I did know that I had a prejudice against electrical engineering. Nevertheless, near the end of my course I began to feel that the performance of electrical apparatus could be predetermined more accurately than that of mechanical. It was this feeling that led me to change my field to electrical engineering in spite of my former prejudices, and later, it was this same feeling that led me to specialize in radio." After graduating from Stevens Institute, Professor Hazeltine entered the testing department of the General Electric Company in Schenectady where he received a practical training. This was his only venture along the highroad of business, for the following year he was offered a position as assistant in the Department of Electrical Engineering at Stevens Institute and he has remained at that college ever since. WHY HAZELTINE SPECIALIZED IN RADIO I WAS fortunate in my surroundings at Stevens," says Professor Hazeltine, "for my work covered all branches of electrical engineering and the head of the department, Professor Albert F. Ganz, was always aiding and inspiring my further progress. During this period I specialized in one branch of electrical engineering after another, and prepared much of the material for presentation to my classes. It was in this manner that I gradually developed a text on electrical engineering, which has but recently been published. "Professor Ganz was the foremost authority in this country on the subject of electrolytic corrosion of underground structures by stray electric current, particularly from electric railways. At times I assisted him in this work and for several years after his death I was associated with the firm of Albert F. Ganz, Incorporated, which continued his professional work in electrolysis." During the winter of 19 1419 15, the wellknown radio experimenter, E. H. Armstrong, wrote a paper, presented before the Institute of Radio Engineers, on the fundamentals of — the three-electrode vacuum tube and then in a subsequent paper described in detail the tube's capabilities for oscillating which he had discovered. The young instructor at Stevens, who had always been partial to any branch of mathematical science, found a new and delightful field before him. Here at last was a real opportunity to apply mathematical analysis. THEORY PRECEDES PRACTISE LONG before Professor Hazeltine had one of the desired vacuum tubes he began a theoretical study of its operation, and it was in this manner that he worked out the theoretical requisite for the production of oscillations. Not until then did he obtain a vacuum tube (then known as an audion) to trace its characteristic curve. On the basis of that information he designed his circuit, wired it, and immediately obtained the anticipated result.