In many respects, Richard Bales, who conducts the National Gallery Orchestra, and Mozart are soul mates. Both revel in the elegance of grace and manners. Style and structure are basic to their discourse, and moderation characterizes their idioms.

At the National Gallery last night, Bales led his orchestra in an all-Mozart program that highlighted these affinities and also revealed some basic differences in their preferences.

The two operatic overtures, from "Lo Sposo Deluso" and "Der Schauspieldirektor," might have been written for the NGO forces. They are cheery pieces that bounce along with classic charm, and Bales had a splendid time with them.

The Masonic Funeral Music, played in memory of the late MacGill James, who was assistant director of the National Gallery from 1940 to 1956, had a somber and sonorous sound, its quiet harmonies augmented by the East Garden Court's echoes into a strong affirmation.

But Mozart and Bales parted company in the readings of the D-Major Piano Concerto K. 537 and the Symphony No. 39. These are works in which detail is important and Bales tends to be a generalist. He is marvelous at making sense of large structures. He exudes the spirit of the music, but in this performance he often glossed over the technical niceties.

The soloist in the concerto was Carlos Moseley, who used to be the managing director of the New York Philharmonic. Clearly he and Bales enjoyed their collaboration, and he demonstrated considerable digital agility in the process, but he left out, along the way, the shaping of phrases, the shading of dynamics and the elasticity of motion that make Mozart worthwhile.