A gentle breeze and a brightly etched evening were all Peter, Paul, and Mary needed for props during a recent performance on the Boston Common. The event was part of a 1982 tour taking them to 35 concerts across the United States.
The folk trio that added ''Blowin' in the Wind,'' ''If I Had a Hammer,'' and ''Puff (The Magic Dragon)'' to the national repertoire deliver their music with a zest that belies the many times they have done it all before. In slacks and button-down shirts, Peter and Paul contrast charmingly with Mary in her elegant long black dress.
Peter and Paul's guitars sometimes sound as rich as organs; the vocals are spendidly blended; and the three play most of the songs they have become known for since they first became a team 20 years ago.
Yet along with the favorites, they serve up new songs for the audience's consideration, including Paul Stookey's tuneful - although biting - ''El Salvador,'' which ends with the line ''Don't you think it's time to leave El Salvador.''
''I am not the activist of the group,'' Paul said to the audience here before he sang his song (referring to Peter Yarrow and his longtime involvement with a variety of political causes). Paul had written it just a month earlier.
The touring concert amplifies Peter, Paul, and Mary's attitude toward their music. If someone points a finger at their rich past - and their repertoire of music strongly evokes the 1960s - they turn their gaze to the present.
When they began touring together again four years ago after a 71/2-year separation, they brought along an electronic keyboard, an amplified drum set, and an electric bass. But they soon forsook electric instruments, although not before making an album Peter himself describes as being ''too heavily embellished'' - their 1978 ''Reunion'' record.
Though they've cut dramatically back on the electricity they need at performances and have returned strictly to the traditional instruments, they continue to look at making folk music as a contemporary process.
''The essence of going to a folk concert is not to feel nostalgia for a particular musical style,'' remarks Mary, ''but to go for music which hopefully will survive whatever moment of popularity it had and go forward. I've gone to so many Pete Seeger concerts in my lifetime, and I've never had a moment's twinge of nostaligia. It isn't in the nature of the music.''
''Our audiences,'' remarks Paul, ''will have their 'Jet Plane' and other songs. But they do not deny us and certainly do not deny the rest of the audience an opportunity to listen to what's currently happening in Peter, Paul, and Mary songdom.''
And the vitality and warmth are the same. In an event that no doubt will be repeating itself on tour, the audience in Boston ended up singing - and, in one case, making appropriate sound effects - with the trio.
''In a folk concert,'' says Mary, ''there is an intellectual faculty that's brought to bear. Certainly an emotional faculty too. And you are not asked to be passive. Most folk concerts end up with a certain segment of the program requiring the audience to sing.''
According to Paul, ''This is not a concert by rote. This is a living, breathing going-on. And we bump elbows and we make mistakes and we take excitement in each other's capabilities and are enthusiastic and encourage each other as well as the audience.''
When asked what the group tries to do for their audiences in a performance, Paul says, ''There is an aspiration that we always have. And that is that our audience might understand the value of quiet, that they might understand the value of being unique in an age that seems to demand compromise.
''Another aspiration would be that the audience comes away feeling that they've experienced an evening together as opposed to just being entertained.''
Peter says, ''We're involved in a bridging idiom that gives people a sense of closeness, ownership of their own lives, and responsibility for their own lives.''
They tour together a small part of the year and spend the rest of the time in their individual pursuits. ''We have a great appreciation for each other,'' says Peter, but he adds that because they are not together all the time ''We are able to live balanced lives.''
Their remaining appearances together this year include: Los Angeles, Sept. 17 and 18; Concord, Calif., Sept. 19; Spokane, Wash., Sept. 22; Portland, Ore., Sept. 23; Seattle, Wash., Sept. 24; Atlantic City, N.J., Oct. 22-24; and Lake Tahoe, Nov. 10 and 11.