The terra cottas going on display today at the National Gallery of Art are as lofty as they are humble. The show is full of nymphs and saints, yet its star is clay.

Terra cotta is Italian for "baked earth," and there is no older sculptural medium. It takes strength, skill and chisels to work a block of marble; sculptors do not doodle in costly molten bronze, but anyone with access to moist clay and fire can work in terra cotta, and countless sculptors have.

The ancient Greeks, the Etruscans and the Romans worked in terra cotta; so, too, in the Renaissance, did such famous Florentines as the della Robbias, Ghiberti, Donatello, Pollaiuolo and Verrocchio. None of them, however, is represented here.

"European Terra Cottas from the Arthur M. Sackler Collections" is not a show that awes. Masterworks are rare here; the labels on the wall are unusually sketchy replete with "circle of," "attributed to" and unfamiliar names. Many of these statuettes, figurines and plaques are preparatory studies. But what they lack in grandeur they make up in charm.

Throughout this exhibition, one feels the artist thinking: How should that fold of fabric fall? Should I smooth out that shoulder? Clay allows broad summaries and fine details as well -- a hero's curing hair, the feathers of an angel's wing. There is much work here of second rank, but the exhibition as a whole is sweet and free and fluid.

Albert Ernest Carrier-Belleuse (1824-1887) is represented here by a superbly modeled scene of a "Bacchante Offering a Libation of a Bacchic Term." Her skin is soft and smooth, her young figure lithe; his head is wreathered in vines, and he seems blissed out by the sight. Giuseppe Maria Mazza (1653-1741) shows us the young David standing on the thigh of the dead Goliath, holding up the severed head. Ottavio and Nicola Tosela, the 18th-century sculptors from Bologna, here portray a miracle -- an 8th-century farmer plowing is attacked by snakes and then, just in the nick of time, rescued by a flock of cranes that swoop down to eat them.

Unlike many of his colleagues here, Claude Michel (called Clodion), the late-18th-century Parisian, is undoubtedly a master. He is represented by a little vestal virgin holding sacred vessels. He makes beige clay appear to silver, skin or steam.

Because they are so delicate, Europe's finest terra cottas -- the few that have survived to enter the museums -- almost never travel. This 60-item show, which surveys terra cottas from the 15th century through the early 20th, looks most appealing at the National Gallery of Art, a museum known for favoring major works by major names and for caring more for painting than it does for sculpture.

Arthur M. Sackler, owner of the collection, is a New York research psychiatrist and magazine publisher who has given art and money to Princeton and Harvard and whose name is on the Sackler Wing of the Metropolitan Museum of Art.

The terra cotta show has been handsomely installed by Gordon Anson of the National Gallery's staff. It will remain on view on the first floor of the East Building through Jan. 27.