George Washington University students who arrived early last night for Paul Arthur Crafton's graduate class in basic qualitative methods for engineering administration were unaware their professor wouldn't be there.

"Good Lord, is he the one?" asked Hank Springer, 35, a senior engineer for maintenance management for the Washington Suburban Sanitary Commission, when told that the "John Doe" professor in the Cumberland County jail in Pennsylvania has been identified by GWU officials as Crafton. "To put it mildly," Springer said, "I'm very surprised."

When the class began at 7:10, the Crafton intrigue was handled simply. Professor John Kaye walked into the room where Crafton was supposed to be teaching, erased the blackboard, took off his coat, told the class, "I am part of the regular faculty," and began his lecture.

The Crafton enigma puzzled others in the 25-student class, who characterized him as a patient, conscientious professor.

Their descriptions contrasted sharply with those of students at Towson State University, outside Baltimore, where University authorities believe Crafton, using the alias David Arthur Gordon, taught from August 1979 to March 1982.

The GWU students said their professor was patient; Towson students said they were intimidated by theirs. GWU students said Crafton hadn't missed a class this semester; at Towson, students said Gordon often excused them two days a week from their three-day-a-week class. GWU students said Crafton spoke with no noticeable accent; at Towson, Gordon stressed that his background and credentials were British, and he spoke with a British accent. At GWU several students said they regarded Crafton as tough but fair; several Towson students have called Gordon harsh and too demanding.

But students at both schools knew their professor by the clothes he wore regularly: "dark blue polyester pants, a white shirt and a belt with a large silver buckle," according to John Brooks, a junior at Towson who took an accounting class from Gordon in 1982.

And students at both schools said their professor suffered from physical ailments. GWU students noted that Crafton was never without a cane, even when at the blackboard. Towson students remarked most on the way Gordon carried his right arm, close to his body as if he couldn't raise it. Students at both schools said their professor's use of his left hand for writing was awkward.

Crafton and Gordon were both remote figures in the traditionally cliquish academic world.

After a quick rise through the academic ranks at GWU, Crafton, now a tenured full professor of engineering administration there, long ago fell far behind his peers in his professional advancement. They were earning as much as $45,000 from their university jobs, plus fees from consulting jobs and research projects that are considered essential to keeping pace in the rapidly changing field.

Crafton hadn't had a raise in eight years. "He did not stand up to the standards we have set . . . ," Sam Rothman, head of GWU's Department of Engineering Administration, said yesterday. "You get paid what you earn."

With his teaching load reduced to part time this year because of what Crafton said were orthopedic-related illnesses, his pay was cut to $14,000--two-thirds of his normal salary.

William R. Brown, chairman of Towson's Department of Business Administration, said Gordon had a "pack of credentials" when he was hired as a visiting professor in the fall of 1979. Gordon claimed to have a doctorate from the University of Edinburgh, but he had never shown Brown anything but photostatic copies.

In December 1981, Brown told Gordon he needed originals of his credentials, but he said Gordon never complied with the request.

In the spring of 1982, Brown said, he understood that Gordon wasn't meeting many of his classes. When Brown confronted him, Gordon resigned, effective the next day.