Clad in knee socks, a plaid kilt, and a tweed jacket, a black hat perched atop his thick, graying red hair, Charles W. Dunn would stand each September outside Harvard University's Quincy House and, to the accompaniment of bagpipes, deliver the residence ``from the malevolence of all banshees, bogles, and kindred evil spirits."
An absence of ghouls was a fringe benefit of living in a house where the master was chairman of the Department of Celtic Languages and Literatures and, more to the point, a Scotsman in good standing. Someone once asked if he thought the annual exorcism actually banished bogles and their goblin brethren.
``Of course it works," he said in an account Harvard published in 1976. ``That's like asking me if I believe in the Loch Ness monster."
Dr. Dunn, who helped invigorate the academic study in the United States of all things Celtic, died July 24 in Beth Israel Deaconess Medical Center after a long period of declining health. He was 90 and had lived in Cambridge for more than 40 years.
``Charles Dunn really played a pivotal role in the development of Celtic studies at the university level in this country," said Patrick Ford, the Margaret Brooks Robinson research professor of Celtic languages and literatures at Harvard. ``We owe him a great deal for making that possible, and for securing a really solid base for Celtic studies in universities."
The son and grandson of Presbyterian ministers, Dr. Dunn was born in Scotland and attended schools in Edinburgh and Aberdeen before his family moved to Boston, where he went to the Rivers School. His family then moved to Canada and he received a bachelor's in English and German from McMaster University in Hamilton, Ontario, where he also studied Latin and Greek.
His love of languages continued, and decades later he would shrug off inquiries as to how many he had mastered, except to suggest the number was high.
While traveling abroad, he and his wife, Elaine, visited a museum ``and at one point Charles was translating and reading aloud. I said, `Charles, what are you reading?' And he said, `Well, Old Norse, of course,' " she recalled. ``He could read a lot of these languages. It's not that he was conversant in all of them. You don't really converse in Old Norse."
Dr. Dunn first arrived at Harvard for graduate studies in English and Celtic philology, receiving a master's in 1939 and a doctorate in 1948. On a postgraduate traveling fellowship, he studied the Scot-Gaelic settlements in Cape Breton and gathered material that would appear in his book ``Highland Settler: A Portrait of the Scottish Gael in Nova Scotia." The trip also served as a honeymoon of sorts for his marriage to his first wife, Patricia Campbell, who died in 1973.
After the fellowship he taught at Stephens College in Columbia, Mo., Cornell University, the University of Toronto, and New York University before returning to Harvard in 1963 to become the third chairman of the Celtic Languages and Literatures department, a post he held until retiring in 1984.
When he became master of Quincy House in 1966, he called himself a ``professional Scot" in an interview with the Harvard Crimson. The student newspaper ran four photos that showed off the waves in Dr. Dunn's thick hair that would do any ocean proud and noted that ``he looks 35 years old but is actually 50."
Dr. Dunn, who was a member of the American Academy of Arts and Sciences, was house master until 1981, a tenure that coincided with the years of student unrest in the late 1960s and early 1970s.
``During the revolution, it was my duty to keep student discussion as open as possible regardless of whether I agreed," he told a Harvard publication in 1976.
Viewing his role as ``a catalyst," he said adept masters helped students learn how to accomplish what they wanted to do at Harvard.
``He changed my life, but I think this is true for any of his students," said Marlyn McGrath Lewis, the director of admissions at Harvard, who was one of Dr. Dunn's graduate students.
Known for his generosity with students, Dr. Dunn turned Quincy House into ``a center for literary and linguistic people from all over the world," she said, and readily shared the company of distinguished guests who visited.
``When you joined the Celtic department, you were a real scholar," she said. ``He treated you as an equal, and he was an enormously learned guy."
``He was so steeped in the Scottish tradition he immediately came across as an authoritative person," said Zeph Stewart, a retired professor of classics at Harvard. ``At the same time he was open and sociable, so he got on easily with all kinds of people, including faculty, students -- or the entire world."
Classes and lectures could be intimate or grand, and they nearly always were performances.
``One of the things he used to do is teach the class in his living room," said Ursula Moore Smith, manager of the Harvard University mail services and a former graduate student of Dr. Dunn's. ``We'd sit in overstuffed armchairs and couches and discuss literature, and he'd invite one or two other professors to join us. He treated all students as if they were charming, interesting adults whose presence he relished."
In the lecture hall, Ford said, he had an almost preternatural sense of timing, ending class at a cliff-hanging moment.
Once, he said, Dr. Dunn was lecturing about a medieval tale in which a ``giant raised the ax high over his head and . . ."
At that moment, the chimes went off and Dr. Dunn would ``snap his book shut and say, `We'll continue this,' " Ford said. ``The students would give their characteristic Harvard moan, which was a moan of affection. He could get away with that because he had a good presence in the classroom."
In and out of class, Dr. Dunn wore suits he had purchased in Scotland and always donned a hat outside.
``He could never understand why these men in suits didn't have hats on," his wife said. ``One of his sayings was, `Always dress for the occasion.' "
He also ``loved his Scotch," she said, ``but it didn't necessarily have to be single malt. As a Scot, he was prudent."
Dr. Dunn's son Alexander, of Worcester, said his father adhered to ``the professor's diet, which was more than just about eating, it was about enjoying things."
As a traveler in Scotland, that meant rarely covering more than 40 miles in a single day, his son said.
``The destination was not the point of the trip," he said. ``I came to realize that it was really about the stops and the little side adventures. He was always up to go over the next hill. `What's over there? Let's go and look.' "
In addition to his wife and son, Dr. Dunn leaves another son, Peter, of Waterloo, Ontario; a daughter, Deirdre Dunn Strachan of Watertown; a grandson and a granddaughter; and two great-grandsons.
A memorial service will be held at 2 p.m. on Nov. 3 in Memorial Church at Harvard.