Bits and pieces from the NSO tour:

National Symphony manager Henry Fogel was not at all unhappy with the final count on Vienna reviews of the NSO at mid-tour. Two years ago, when he was traveling with the New York Philharmonic, Vienna gave that orchestra and its conductor, Zubin Mehta, two bad reviews and one good one. The NSO ended up with four good notices and one poor one. (Mehta had warned his New York colleagues ahead of time exactly what would happen in Vienna.)

The tour produced fresh evidence that music reviewers are contradictory. For example, in Mannheim, critic K.H. thought, "The work's Schubert Third charm and songfulness did not appear. Schubert does not deserve such coolness." While in Vienna, Franz Endler found "Schubert's 3rd was played with charm and warmth, and it came out very beautifully." Obviously one man's warmth is another man's coolth, while charm is clearly in the ear of the beholder.

Another difference arose over the orchestra's brass section: In Vienna it was described as "thunderous," while the Amsterdam Handelsblad critic said "the copper sic is the weakest, especially in the tender episodes." Since there are close parallels in the acoustics of the two halls, the aural discrepancy cannot be charged to differences in locales.

Chrissalene Petropoulos, the gifted young soprano who grew up in Potomac, Md., is now singing with the Vienna State Opera. A week ago Monday night she sang the small role of Tebaldo in Verdi's "Don Carlos." Next summer she leaves Vienna, where she has been singing for two years, to become one of the leading sopranos in the Kassel Opera, singing Norina, Zerlina, Amina, Gilda, Pamina and other roles that are just right for her voice at this time. Prediction: You will be seeing and hearing Petropoulos in major opera centers before long.

In two visits to the world-famed State Opera, it was quite apparent that Vienna is suffering the same afflictions as the world's other big houses: a serious shortage of principal sopranos, tenors and conductors. A "Macbeth" offered Mara Zampieri as Lady Macbeth, singing loudly but not beautifully. Also in Vienna, they make a practice of the barbaric business of permitting, indeed encouraging, prolonged applause after every aria. During the applause the principals bow, gesture, incline their heads, encouraging the applause to go on as long as possible. Arturo Toscanini walked out of La Scala because of this sort of thing 80 years ago. Perhaps Lorin Maazel, moving into the directorship in Vienna, will be able to put a stop to it. It is worse than any behavior I ever saw in the most provincial opera house.

Conductor for the "Don Carlos" was Miguel Gomez Martinez. Every time he appeared, he was hissed loudly. It seemed appropriate in view of the results he produced.

At 5 o'clock last Friday afternoon, with his Salle Pleyel concert only three hours away, Mstislav Rostropovich and his wife, Galina Vishnevskaya, gave a sumptuous tea in their new Paris home on Avenue Georges Mandel. Asked why he was adding that kind of social obligation to his heavy schedule, Rostropovich answered, with his most embracing smile, "Because I want to welcome my friends to my home." The apartment is magnificently appointed with furniture, china, paintings and objets d'art from pre-Revolutionary Russia. A table of malachite, standing near a chair that belonged to Catherine the Great, is surrounded by other pieces in the same exquisite shade of green; the drapes were in the Winter Palace in St. Petersburg. A tall cabinet is filled with exquisite pieces of hand-painted china, decorated in gold. The walls hold drawings by Dufy and paintings by Kandinsky. At the moment, because of the need for room for scores and papers, four Chagalls are in storage. Eventually they should find just the right place in the apartment, whose chatelaine, Vishnevskaya, presided over a tea where the tartes aux pommes, aux poires et aux framboises were enough to cause strong men to leave home.

The orchestra winds up its tour this week with concerts in Brussels, Hamburg, Barcelona and Madrid. The Spanish capital is the home of the NSO's principal guest conductor, Rafael Fruhbeck de Burgos, who is throwing a party for the whole orchestra after its concert tomorrow. On Friday the musicians fly home. Next week, under Fruhbeck's direction, they will play their customary subscription concerts in the Kennedy Center.