BY W. SPENCER BLOOR

Nathan Cohn, active for more than sixty years in the measurement and automatic control field, a pioneer in the development and application of control techniques for interconnected electric power systems, and elected to the National Academy of Engineering in 1969, died in Scottsdale, Arizona, on November 16, 1989, at age eighty-two.

Nat, as he was called by those who knew him well, was born in Hartford, Connecticut, January 2, 1907. Following graduation from the Massachusetts Institute of Technology in 1927, he joined the Leeds & Northrup Company and remained with the firm for forty-eight years. He retired from his position of executive vice-president in 1972 and from corporate director in 1975. Following his Leeds & Northrup retirement, he remained active presenting invited lectures, serving as corporate director of several technologically-oriented companies, devising new patented techniques for improving interconnected power system operational performance and control, authoring and presenting technical papers, working as senior technical associate of Network Systems Development Associates, and participating in volunteer work. Nat's engineering career was distinguished by both personal achievement and leadership of others.

In the field of control of interconnected electric power systems, he was a world-renowned authority. He authored ninety technical papers and a book. He was granted fifteen patents and established several interconnected system operating practices. Many of his patents and practices are widely used in the electric utility industry, and his publications, in the education of electric power engineers. In his specialty, he was in demand as a lecturer both in the United States and abroad. Included in the list of countries where he lectured are Canada, Brazil, Colombia, Peru, Russia, and Yugoslavia. For his personal technical achievements, Nat was elected a life fellow of the Franklin Institute, the Institute of Electrical and Electronics Engineers (IEEE), and the Instrument Society of America (ISA); and was awarded the Franklin Institute's John Price Wetherill Medal, the IEEE's Lamme Medal, and ISA's Albert F. Sperry Founder Award.

Nat's engineering leadership carried the hallmark of constructive accomplishment. Thorough advance preparation, well-understood plans, attention to the details of implementation, and high standards of excellence in results were characteristics of his leadership. During his ten years as vice-president of research and engineering at Leeds & Northrup, the company enjoyed a period of exceptional productivity in its output of new products of outstanding merit. His terms as president of the National Electronics Conference, the ISA, and the Scientific Apparatus Makers Association; and as chairman of the Franklin Institute's board of managers, the IEEE's Fellows Committee and Awards Board, and the Intersociety Hoover Medal Awards Board were marked by innovation, achievement, and the esteem of those he led. For leadership and career accomplishments, he was awarded the IEEE's Edison Medal, the Scientific Apparatus Makers Award, and honorary membership in the ISA; and made an adviser to the International Federation of Automatic Control.

The list of his services as member or chairman of committees or volunteer organizations is too long to recount in full. For the National Academy of Engineering, Nat chaired the Electrical Engineering-Communications/ Computers/Control Peer Committee in 1975 and the Committee on Membership in 1977. For the National Research Council, he chaired the National Bureau of Standards Advisory Panel on Time and Frequency from 1969 to 1971 and the Panel on Instrumentation of the Physics Survey Committee from 1970 to 1973. For his alma mater, the Massachusetts Institute of Technology, he served on the visiting committees for libraries and philosophy. In the Philadelphia community, he was vice-president of the Eagleville Hospital Rehabilitation Center and a trustee of Keneseth Israel Reform Congregation.

Nat was a member of Eta Kappa Nu, Sigma Xi, and Tau Beta Pi, and received an honorary doctor of engineering from Rensselaer Polytechnic Institute in 1976. He was an avid sports fan and enjoyed boating, fishing, golf, and outdoor cooking.

He is survived by his wife of forty-nine years, Marjorie; their five children, Dr. Theodore E. of Berkeley, California, Dr. David L. of South Bend, Indiana, Dr. Anne H. of Chicago, Illinois, Dr. Amy E. Cohn-Tucker of New York City, and Julie Cohn Conner of Houston, Texas; and eight grandchildren.