The Boston premiere of a new symphony by Walter Piston highlighted the pair of concerts given last weekend by the Boston Symphony Orchestra, Charles Munch conducting. The symphony, Mr. Piston's fourth, was commissioned by the University of Minnesota and first performed as part of that school's centennial celebration in the spring of 1951.

I don't know whether a composer always intends that there be a connection between the spirit of the occasion for which a work is commissioned and the spirit of the work itself. In the case of Mr. Piston's latest two symphonies, however, such a connection, seems to be suggested. The third Symphony, commissioned by the Koussevitzky Fund was dedicated to the memory of Natalie Koussevitzky. That gripping and often somber work won the Pulitzer Prize in the year of its premiere, 1948.

The Fourth Symphony exhales an altogether different atmosphere . . . gay, melodious, sometimes downright boisterous. Its easy appeal, even at first hearing, may soon make it one of the most popular of contemporary American symphonic works.

The symphony exemplifies Mr. Piston's well-known mastery of the classical forms, a mastery which includes freedom in their manipulation as well as overall adherence to them. The first movement, marked Piaccoole (pleasant), opens with a smooth, easy-going melodic line. Although is the climaxes this melody is transformed into a vigorous and exciting rhythmic force, the movement as a whole has a restrained air about it and fully bears out its unusual appellation.

The second movement is the piece de resistance of the symphony. Marked Ballando (dancing), the form is that of a rondo, one of the most characteristic of the classical forms; but the material which comprises it is anything but classical. The main section, written largely in irregular meters, is a wild affair with much brilliant display by the brasses. One of the contrasting sections is a sentimental waltz tune. The movement also includes one of Mr. Piston's rare samples of folk Americana, a country fiddler's tune.

The third movement, Contemplativo, maintains an almost unbroken and highly expressive melodic line. Through much of the movement there is a subdued, delicate orchestral texture from which now one voice, now another emerges with the melody. The final Energico, in regular sonata-form, proceeds quickly, leaving the audience in high spirits.

If the overall impression of the work was not as overwhelming for me as its many merits would indicate, it is perhaps only that I miss a powerful climactic movement. The Piacevole hasn't enough drive to fulfill this need and the Ballando, while possessing plenty of drive, can't be taken seriously enough to fulfill it.