By RICHARD SEVERO 

Betty Furness, who went from minor acting roles to reknown as a television saleswoman and then became a formidable consumer advocate, died on Saturday at Memorial Sloan-Kettering Cancer Center in Manhattan. She was 78 and lived in New York City and Hartsdale, N.Y.

The cause was stomach cancer, said her husband, Leslie Midgley.

With the cheekbones of a model and the directness of a New England schoolmarm, Miss Furness was one of the true pioneers in television consumer journalism. In her heyday with WNBC-TV in New York, she regularly broadcast the names of errant businesses and shoddy products. She pointed television cameras at stores where New Yorkers had been cheated, and lectured the proprietors. She reported on hamburger that was too fat, on warranties that were too lean, on gadgets that were too temperamental and on business ethics that she saw as seriously flawed. She even scolded Macy's.

Park Avenue Upbringing

Miss Furness essentially created a place for consumer advocacy on local television. She also spent a great deal of time off the screen promoting the cause of consumer justice. She was on the board of Consumers Union, which publishes Consumer Reports magazine, from 1969 until she retired for health reasons in 1993, and she worked for Common Cause. She also was President Lyndon B. Johnson's special assistant for consumer affairs and was head of the New York State Consumer Protection Board in 1970 and '71. She was Commissioner of the New York City Department of Consumer Affairs in 1973.

Miss Furness, who had surgery for stomach cancer in 1990, was eased out of the "Today" show on NBC in 1992 after 16 years with the program. "This was their idea, not mine," she said dryly as she departed.

Miss Furness, whose original name was Elizabeth Mary Furness, was born on Jan. 3, 1916, in New York City, the daughter of George Choate Furness, an executive with what was then called Union Carbon and Carbide, and Florence Sturtevant Furness. The Furness family was well off and young Betty was raised on Park Avenue and sent to the Bennett School in Dutchess County, N.Y. In 1932, before graduating, she dropped out to become an actress.

It was the Depression, and her father had advised her to learn "something useful." She got summer jobs with the John Robert Powers Modeling Agency, but to her father's dismay earned only $80 in two summers of work. But she was blonde and trim, and Mr. Powers noticed her. He liked the way she used her voice and her gray-green eyes, and he arranged for her to take a screen test at RKO.

The only acting she had done was in school theatricals, but just a year after she left the Bennett School, RKO was touting her as a bright new talent. She had secondary roles in 35 films in Hollywood and later called them all appalling except "Swing Time," which starred Fred Astaire and Ginger Rogers, and "Magnificent Obsession," both produced in the mid-1930's. She left the screen in 1937 and moved to the stage. With few exceptions -- the stock and road productions of "Golden Boy," "My Sister Eileen" and "Doughgirls" -- the career that had started with promise seemed to be going nowhere.

Early TV Participant

In 1948, with commercial television just starting, Miss Furness landed a job with the DuMont Television Network, which signed her to do a 15-minute show called "Fashions, Coming and Becoming."

A year later, somebody at Westinghouse saw her in a "Studio One" drama and offered her a job as the company's representative on television. For more than 11 years Miss Furness was a staple on evening television, frequently standing in front of refrigerators and waxing eloquent about their performance.

In 1952, 1956 and 1960, Miss Furness did the Westinghouse commercials during the Republican and Democratic National Conventions and developed a strong interest in politics. She worked for Abraham Ribicoff in Connecticut when he made his first successful race for the United States Senate in 1962. After meeting Lady Bird Johnson and Muriel Humphrey, she also made recruiting trips for Head Start and Vista, the Volunteers in Service to America.

Left Rockefeller Job

In 1962, she was the hostess of a five-minute radio show called "A Woman's World," in which she talked about food, clothes, child rearing, family relationships, teen-agers and the aged. Late in 1962, she worked on an ABC-TV show called "Answering Service." The show was nominated for an Emmy Award, but ABC dropped her all the same.

Miss Furness abruptly quit as Gov. Nelson A. Rockefeller's consumer affairs adviser in 1971, charging that the New York State Legislature did not take her recommendations seriously enough. She ran New York City's Department of Consumer Affairs in 1973. After that she worked briefly for McCall's magazine as a contributing editor and wrote a column for consumers.

Despite the number and diversity of her activities, she was never able to completely shake off her image as a product saleswoman. "I feel I'm a very serious person who wants to do things," she once said, "but people keep talking about refrigerators. I'm tired of telling the story about the refrigerator door that didn't stick, and I'm bored with the image."

In 1937 Miss Furness married Johnny Green, the composer and conductor, with whom she had a daughter, Barbara. The couple divorced in 1943. In 1945, she married Hugh B. Ernst, a radio announcer, who died in 1950. She married Mr. Midgley, a CBS News producer, in 1967.

In addition to her husband and her daughter, she is survived by three stepchildren, Leslie Midgley, Andrea Connors and Peter J. Midgley, and two grandchildren.

Copyright 1994 The New York Times Company