An almost immeasurable artistic distance lies between the "1812" Overture and Tatiana's "Letter Scene" from "Eugene Onegin," both of which were featured in the National Symphony Orchestra's all-Tchaikovsky program Saturday night at Wolf Trap. The two are the work of the same melodic and dramatic genius, but they seem to come from different universes.

The "1812" is a spectacular battle piece, symbolizing Napoleon's doomed invasion of Russia in a pitched battle between the "Marseillaise" and an old Russian hymn, and ending triumphantly with cannon shots, jubilant bells and an orchestral uproar. The letter scene, a 15-minute soprano showpiece, presents a young woman in her teens experiencing the agonies and exultation of first love and pouring it all into a letter that she dashes off impetuously to the man who has awakened her womanhood. It is as subtle and sensitive as the "1812" is splashy and spectacular.

These two works triumphantly concluded the program in excellent performances for which credit must be shared by the orchestra, conductor John Nelson and Canadian soprano Irena Welhasch Baerg. Earlier, Nelson conducted a performance of Tchaikovsky's Fifth Symphony that was slightly more restrained than we are accustomed to hearing with Mstislav Rostropovich on the podium but beautifully shaped and controlled. The Ecosaise from "Onegin" was a pleasant trifle that allowed Baerg to catch her breath after a very expressive performance of Lisa's aria from "The Queen of Spades." In both arias, Nelson was a most considerate partner, tailoring the orchestral sound to support the voice, engage it in dialogue but never cover it.