One handsome fragment of Washington's small-town past that has escaped the wrecker's ball is the spare and elegant original synagogue of Adas Israel.

The red-brick building, erected in 1876 by the then-struggling splinter group of Washington Hebrew Congregation, was plucked from the demolished block that became Metro Center. After Adas Israel outgrew it, the building had served as St. Sophia Greek Orthodox Church of God. After World War II it became a grocery and finally a lunchroom.

Now restored to nearly its orginal condition on new foundation at Third and G Streets NW, the synagogue suggests a 19th-century Quaker meetinghouse. The interior proportions and serene simplicity speak of a time and a community fitted to the human scale.

The building, designated a National Historic Shrine, now serves as the Jewish Museum of Washington. On Sunday the museum will open to the public a modest exhibit called "The Way We Were, 1876-1910," including photographs and memorabilia of Washington's 19th-century Jewish community.

Director Hadassah N. Thursz has made a virtue of severity and limited scope in her selection. "It is a small museum and we make no pretense otherwise," she said. The result is a homey, witty and evocative addition to our town's minor treasures.

The museum is open Sundays from 10 to and weekdays of appointment (789-0800).