Stephen Douglas Burton's Variations on a Theme of Mahler begin, according to the composer's instructions, "Dreamily," and in the next 20 minutes or so take the orchestra and the audience on a voyage through some fascinating and partly unfamiliar landscapes.

This work, which had its first performance last night, is another example of the trend, still gaining strength, in which American composers are exploring some of the new things still to be said in a fairly traditional language.

The melody is an apparently simple little tune -- a setting by Gustav Mahler of a folksy poem about a fisher maiden whose net catches men's hearts rather than fish. But it has implications, explored and invented by Burton, that are dramatic, playful, agitatated, peaceful and hospitable to a wide variety of instrumental flavors and statements. At times the music might be taken as a sort of advertisement for Burton's textbook on orchestration, which was published earlier this year. He demonstrates that his knowledge of this art goes far beyond pure theory, and in the process he gives all of the principal players in the orchestra some delectable solo material.

Their appreciation of this thoughtfulness was evident in last night's first performance in the Harris Theatre at George Mason University, where Burton is a member of the faculty. Alvin Lunde conducted the Washington Chamber Orchestra, which commissioned the new work and made it sound like a permanent, significant addition to the small but growing chamber orchestra repertoire.

Among the melodies' possibilites, Burton finds a ragtime tune that he puts in his fifth variation, marked "With a Swing." There are also a scherzo, a waltz, a fugue and a grand finale that surveys the various flavors already tasted before ending with a grand flourish. It is more than a charming piece of music, but charm is one of its salient qualities and should not be underestimated.

Two other charming composers were on the program: Haydn and Mozart, and Burton's music felt completely comfortable in their company. Haydn's 38th Symphony is in C major, as were all of the pieces on the program, and this festive key supplied an appropriate mood for a festive occasion. The Haydn is nicknamed "Echo" because of a dialogue in the slow movement between the first and second violins, in which the seconds limit themselves to muted repetition of what has just been said by the firsts. The choice of Mozart's 34th Symphony to conclude the program was interesting and agreeable, partly because Mozart has occasional echoes that seem to echo those of Haydn, but mostly just because it is a very enjoyable work. As published, this symphony lacks a minuet, but conductor Lunde supplied the detached Minuet in C, K. 409. It was composed at about the same time, possibly to go with this symphony, and fits very well into its continuity.

The orchestra, with 21 strings, doubled winds, harp and tympani, gave vigorous, well-balanced and delicately nuanced performances of all three works. Lunde has built a first-class little ensemble capable of handling many works, particularly of the 18th and 20th centuries, that do not always receive sufficient attention from larger and more glamorous orchestras. The program will be repeated at 8 p.m., Monday, Oct. 18, in the Lisner Auditorium, and I recommend it to those who have been afraid of contemporary music as well as those who like stylish performances of Mozart and Haydn.