Rutherford Aris, a distinguished chemical engineer who, as the result of a mix-up three decades ago, had a short-lived but supremely accomplished alter ego Aris Rutherford, with an official entry in Who's Who died on Nov. 2 in Edina, Minn. He was 76.

The cause was complications of Parkinson's disease, according to the University of Minnesota, where he was Regents professor emeritus of chemical engineering and classics.

Aris Rutherford, also on the faculty at Minnesota, was a professor of distillation practice, a highly evolved form of chemical engineering. Had he in fact existed, Rutherford, who was slightly younger than Aris, would have been 75.

Curiously, Aris was indeed accomplished enough for at least two people. Originally trained as a mathematician, he went on to become a chemical engineer, doing seminal work in both disciplines.

A skilled classicist, he was also a widely respected scholar of paleography, the study of ancient writing. An accomplished calligrapher, he wrote a book on the historical evolution of letterforms.

His scholarly publications appeared in an unorthodox array of journals, from Chemical Engineering Science and Mathematical Biosciences to New Literary History and The Thoreau Quarterly.

Aris, known as Gus, was born in Bournemouth, England, on Sept. 15, 1929, the son of Algernon Pollock Aris and the former Janet Elford. At 16, he completed a bachelor's degree in mathematics at the University of London; the university, reluctant to grant a degree to one so young, did not officially confer it until 1948, when he was 19.

In 1955, after a stint in industry, Aris joined the University of Minnesota as a researcher; three years later, without a doctorate, he was hired by the department of chemical engineering and materials science. His work, which involved the mathematical modeling of chemical reactions, contributed to the design of safer, more efficient chemical reactors.

Aris earned a Ph.D. by correspondence from the University of London in 1960; he received a doctor of science degree from the university in 1964.

Eminent in his field, Aris soon rated an entry a real one in Who's Who in America. But sometime in the early 1970s, Who's Who also requested a biography from Aris Rutherford.

Aris wrote back and explained the mistake. But the requests continued, each more officious than the last. What could the professor do but oblige?

And so, in the 38th edition of Who's Who in America (1974-75), Aris appears twice: in Volume 1 as himself, and in Volume 2 as Aris Rutherford, who leaps to life in 16 lines on Page 2,672.

In this farcical account, Aris MacPherson Rutherford was born in Strath Spey, Scotland, on April 10, 1930, the son of Archibald MacPherson Rutherford and the former Ephygeneia Aristeides. In 1948, when he was just 18, he earned a diploma from the Strath Spey and Glenlivet Institute of Distillation Engineering. Several advanced degrees followed.

In 1955, after a stint with the Argyll and Sutherland Regiment, Rutherford became the chief design engineer and tester for the Strath Spey Distillation Co. He came to the United States the next year.

From 1960 to 1964, when he joined the Minnesota faculty, Rutherford was a visiting professor of distillation practice at the Technological Institute of the Aegean, in Corinth.

He wrote three books, "Sampling Techniques" (1957), "Distillation Procedures" (1963) and "American Football: A Guide for Interested Scots" (1960).

Rutherford survived only a year. When the news media got wind of the hoax, Aris came clean, and Who's Who expunged his doppelganger from future editions.

Aris' own books, all very real, include "The Optimal Design of Chemical Reactors" (Academic Press, 1961); "Mathematical Modeling: A Chemical Engineer's Perspective" (Academic Press, 1999); and "Explicatio Formarum Litterarum The Unfolding of Letterforms: From the First Century to the Fifteenth" (St. Paul: Calligraphy Connection, 1990).

A former Guggenheim fellow, Aris authentically belonged to many learned societies, including the American Chemical Society, the Society for Mathematical Biology and the Society of Scribes and Illuminators.