Myrtle Cheney Murdock, 94, who came to Washington in 1937 as the wife of an Arizona congressman and became an expert on the history of the U.S. Capitol, died of pneumonia Wednesday in a nursing home in Media, Pa.

Before coming to Washington, she had taught school in Missouri at the age of 15, been an instructor on a Cherokee Indian reservation in Oklahoma, and served on the faculty of Phoenix Junior College in Arizona.

After coming to Washington, Dr. Murdock became interested in the building in which her husband worked. Of particular interest to her was the life and work of Constantino Brumidi, the Italian-born artist who spent 25 years decorating the Capitol. He was killed in 1880 when he fell from a scaffold while painting the frieze near the top of the Rotunda.

Dr. Murdock compiled notes on the Capitol artist and wrote his biography, "Constantino Brumidi: Michelangelo of the United States Capitol." As part of her research, she located Brumidi's unmarked grave in Glenwood Cemetery in Southeast Washington, and later painted the fence surrounding his grave.

Her husband, representative John R. Murdock (D-Ariz.), introduced a bill that was signed into law in June 1950, which provided a bronze and stone marker for the grave.

In addition to her biography of Brumidi, Dr. Murdock's books included "Your Uncle Sam in Washingtion," a collection of weekly columns she wrote for the Arizona Republic newspaper, and works on Washington's memorials and monuments.

Dr. Murdock earned a bachelor's degree at Missouri State Teachers' College and a master's degree at the University of Arizona. She attended night classes at George Washington University and earned a doctorate in education in 1940.

While working in her husband's office and writing her books, she also taught at George Washington University. One of her courses was called "Know Your Capital City." Dr. Murdock said her prize student in that course in 1951 was a woman cab driver.

Dr. Murdock was active in the Daughters of the American Revolution and the Capitol Historical Society and has served as president of the 75th Congressional Club, an organization of wives of representatives elected in 1936.

Dr. Murdock was a Capitol Hill guide from 1953 until she retired in 1966.

Her husband, who became Interior Committee chairman, was defeated for reelection in 1952. The Murdocks returned to Arizona in 1968. Following her husband's death in 1972, Dr. Murdock moved to Media, Pa.

Dr. Mudrock was born in Navoo, Ill., and reared in Missouri. She was awarded the Star of Italian Solidarity in 1951 for her work on Brumidi, and was named Washington Mother of the Year in 1960.

Survivors include a daughter, Rachel M. Ellis of Scottsdale, Ariz.; a son, John B., of Moylan, Pa.; six grandchildren, and two great-grandchildren.