In last Sunday's issue of Potomac Magazine in the Summer at a Glance calendar, the National Collection of Fine Arts presentation, Kaleidoscope Day, should have been scheduled for June 4.

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So, loosen up your collars. Grab a blanket or a bench or just lie back in the grass and enjoy the abundance of local outdoor activity in the hazy months ahead.

There are concerts noon and night in local parks and plazas. In amphitheaters are mimes and puppets. Many events are free, cultual bonanzas courtesy of various recreation departments and the "Summer in the Parks" program run by the National Park Service.

Just use your eyes and ears and maybe a little cash. Take a river boat cruise down the Potomac to Mount Vernon. A sound-and-light show there dazzles visitors nightly. Rent a paddle-boat at the Tidal Basin and attend free military band concerts at the Jefferson Memorial. Combine picnics and the stars for romantic nights at Fort Dupont Park Summer Theater on [PARAGRAPH ILLEGIBLE]

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The best calendar of folk life and music festivals in the country is issued in book form by the National Council for the Traditional Arts, located in the Dupont Circle Building. Entitled simply Calendar of Festivals, it's all-inclusive. Call 296-0068 for information.

"Weather permitting" is the golden rule of outdoor scheduling. Remember to confirm your dates. These telephone numbers will be handy: Weather information, 936-1212; National Park Service "Dial-a-park," 426-6975; Smithsonian Institution "Dial-a-museum," 737-8811.

With that advice in mind, here are the outdoor continuing activities and special events for the summer. Continuing Activities The District

[PARAGRAPH ILLEGIBLE] on the historic C & O Canal. Tickets are available after 10 a.m. daily, for use on a sameday basis, at the Canal Information Center in Georgetown's Foundry Mall at 1055 Thomas Jefferson St. NW. (Adults $2, children $1.) National Park Service rangers in nineteenth-century dress narrate the two-hour ride; music, cider and baked goods complete the old-timey mood. Call 299-4159.

Renaissance and baroque music fill the red brick courtyard of Georgetown's Canal Square, 1054 M St. NW., every Saturday from 1 to 2 p.m.

Streets for People invites downtown Washington to noontime concerts Tuesdays and Thursdays at the city's new pedestrian malls: Gallery Place on F Street between 7th and 9th Streets NW; and Library Place on G Street between 9th and 10th Streets NW.

The American Folk Life Center of the Library of Congress, 10 1st St. SE, presents noon folk music concerts for visitors to the Library's Neptune Plaza, a pleasant two-level terrace graced with green-umbrellaed picnic tables and an Art Nouveau fountain.

Free, creative educational theater is what D. C. City Camp is all about. Archaesus Productions, Inc. and the departments of recreation of the District of Columbia, Alexandria and Prince George's County cooperate to bring professional mime and participatory drama to children in area parks, Tuesdays through Saturdays in July and August. Call Archaesus at 362-7032 for brochures, schedules and reservations.

The National Park Service is clearly the Billy Rose of Washington's outdoor season. The dozens of free NPS "Summer in the Parks" programs operating on parkland throughout the National Capital area create a luxurious, festive mood for us all.

Here are some NPS evening highlands:

The Torchlight Tatoo is a pageant/concert staged by the Army Band on Wednesday nights at 7:30 p.m., July 6-August 31, at the Jefferson Memorial. Up to 8000 people a night attend this wild and woolly music-drama recounting an abbreviated history of the Army, from Revolutionary War days through the Civil War to the present.

Fort Dupont Summer Theater's season runs June 25 to August 28. Free performances at the outdoor amphitheater at Minnesota Avenue and Randle Circle SE include appearances by Alvin Ailey Dance Repertory Company, Lou Donaldson, Grant Green, jazzist Bobbi Humphries and the African group "Dinizulu." Call dial-a-park.

The Marines take their bow at 8:30 p.m. Friday nights, May 20-September 16, in a military ceremony at the Marine Barracks, 8th and I Streets SE. The performance includes pass and review, presentation of colors, and a silent drill. Free, but call three weeks in advance for reservations, 433-4681. Maryland

Glen Echo Park presents "The Chautauqua Summer" Sundays, July 10 through August 28. The special afternoon series features carrousel rides, paint-ins, fiddling and mime performances, and workshops on subjects ranging from solar heating to bicycle tuning to clog dancing to clowning. The converted amusement park is located on MacArthur Boulevard in Glen Echo.

Prince George's Puppet Players will perform at Watkins and Clearwater Nature Centers and other parks this summer. Call 277-2200, ext. 394, for schedule.

St. Mary's City, Maryland, stages a unique historic pageant, "Wings of the Morning," annually, Wednesdays through Sundays, June through August. The drama, which traces Maryland's historic beginning, is performed on a floating stage and viewed from shoreside seats. Call 301/863-5650 for information.

Cabin John and Wheaton Regional Park Concert Series kicks off at Cabin John Thursday, June 23, with "Bavarian Schulplatters and Band." The Air Force "Air Men of Note" come to Wheaton Park Tuesday, June 28. The free 7:30 p.m. variety concerts, sponsored by Montgomery County, alternate weekly throughout the season, one week at Cabin John (Thursdays), the next at Wheaton (Tuesdays). Virginia

Wolf Trap Farm Park For The Performing Arts in Vienna, Virginia, offers free interpretive programs for children, weekdays in July and August, including performances by the Bob Brown Marionettes and audience participation adventures staged by Interplay Productions and by Archaesus Productions. Call 281-5587 for information and, after June 5, for reservations.

Alexandria's Lunch Bunch Concerts begin June 1 in Market Square located at King and Fairfax Streets. Expect free tunes Wednesdays at noon, courtesy of the Alexandria Department of Recreation.

Fairfax County's Touring Puppet Theater performs free puppet shows and workshops weekdays during July and August, as part of the County Summer Playground Program. Call 691-2671 for information.

The Bealton Flying Circus is a fantastic relic, a one-of-a-kind "barnstorming" event featuring open-cockpit bi-plane aerobatics. At Bealton Airport (on Route 17 between Fredericksburg and Opal, Virginia) 2:30 p.m. Sundays, May to October, weather permitting. Adults $4, children $1. Call 256-3676 or 703/256-0139 for information.

The Marine Corps silent drill team and drum and bugle corps perform a "Sunset Parade" at the Iwo Jima War Memorial Monument Tuesdays, 7:30 to 9 p.m, June through August. No reservations necessary. Bring a blanket for this very informal affair.A shuttle bus carries visitors between Arlington National Cemetery parking lot and the Monument before and after the performance.

Arlington County's free "mini-Wolf Trap series" at Lubber Run Amphitheater opens at 8 p.m. June 19 with an old-time country evening of folk arts and music, followed in succeeding weeks by music, mime, film, variety shows and drama. Call 558-2161 for information. Lubber Run is at N. Columbus and 2nd Streets.

Mount Vernon again presents "The Father of Liberty," a sound-and-light show which France gave to the U.S. as a Bicentennial gift. The forty-seven-minute show employs seemingly magical uses of colored lights and music to evoke scenes from George Washington's life. Nightly, 9 p.m., May 27-September 5. Admission is $1.50, free for children under six years.

Note: For a special treat, cruise down the Potomac to Mount Vernon from Washington aboard a Wilson Boat Line Cruise. The boats sail nightly at 7 p.m. from Pier 4, 6th and Water Streets SW. The round-trip fee is $5.50, $2.75 for children under 12 years, and includes the sound-and-light show admission. Special Events

June 3-5. Indian Springs Bluegrass Festival, held at Indian Springs KOA Campground, 15 miles west of Hagerstown. Festival runs from 7 p.m. Friday to 8 p.m. Sunday. Admission charged; camping free. Highly reputed music festival sponsored by the little magazine, "Blue-grass Unlimited," Box 11, Broad Run Run, Virginia, 22041. Call 703/361-8992.

June 4. "Eighth Annual Kaleidoscope Day: The Third Dimension" will be held 10 a.m. to 4 p.m. in the Courtyard of the National Collection of Fine Arts, 8th and G Streets NW. The Smithsonian-sponsored family day is tailored to children aged five to thirteen years.All are invited to participate in dance, music, free-form sculpting, treasure hunts, tours and films. No one goes home empty-handed. Free. Call 381-5503.

June 4. The arts, crafts and music of "Marlboro Day" annually turn Main Street of Upper Marlboro, Maryland, into a street festival celebrated by all Prince George's County. From 10 a.m. to 5 p.m. Call 277-2200, x-394 for information.

June 4, 11. The annual "Boomerang Festival" sponsored by the Smithsonian Associates opens at 10:30 a.m. June 4 with an hour-long lecture/workshop in Baird Auditorium of the Natural History Museum at Constitution Ave. and 10th St. NW. Learn to carve, throw and catch your boomerang and be ready for competition the following week. On June 11, the action moves to West Potomac Park for a second carving workshop, 1 to 3 p.m., and the throwing competition, 3 to 4 p.m., which is officiated again this year by national boomerang expert Ben Ruhe. Free, no reservations. Call 381-5157.

June 4-12. Come to the "36th Annual Outdoor Art Fair" at President's Park, 15th and E Streets NW, and have a ball. Daytime art exhibits, demonstrations by artists and live entertainment are supplemented by do-it-yourself art corners for children and adults. Call the D.C. Department of Recreation for information, 673-7635.

June 5, 12. The D.C. Community Orchestra performs at 4 p.m. at the annual Outdoor Art Fair at President's Park, 15th and E Streets NW. The program features arias from favorite operas, including Humperdinck's overture to "Hansel and Gretel," Rossini's ballet music from "William Tell," and Bizet's "Carmen Suite."

June 12. Glen Echo Park's "Festival of Washington" celebrates Washington's marvelous mix of culture and traditions from noon to 6 p.m. at the park on MacArthur Boulevard. The carnival, planned by the Folklore Society of Greater Washington, promises "a varied sampling of American folk traditions, spiced with music and dance from the far (and near) corners of the world."

June 17-19. "Annapolis Arts Festival" brings blue-grass, jazz and traditional American music to the City Dock in Annapolis. Festivities run from 11 a.m. to 11 p.m. on Saturday and Sunday, and 11 a.m. to 7 p.m. on Monday.Admission charged; no camping. Call Jean Jackson at 301/267-7922 for information.

June 17-19. "Country Gentlemen Blue Grass Festival" is held at Lake Whippoorwill just outside the town of Warrenton on Route 29-211. Admission charged; camping available. Call Ticketron or Robert Foley, 703/347-2500, for information.

July 9. Alexandria celebrates its 229th birthday in a city birthday party from 1 to 4 p.m. at Chinquapin Park, 3211 King St. Free. Call 750-6325 for information.

July 16, 17. "Gunston Hall Arts and Crafts Show" presents period-costumed craftsmen performing eighteenth through twentieth-century specialties. The show is set against the back-drop of the home of George Mason built in 1755 in Lorton. Call 550-9220 for information.

July 17. "Caribbean Summer in the Parks '77" salutes the Caribbean experience in Washington from noon to dark at Meridian Hill (Malcolm X) Park, 16th and Euclid Streets NW. A free festival of dance and music. A dozen local bands will be on hand to play music that brings to mind the blue crystal water of the islands: Jamaican reggae, steel bands, drums, calypso bands and singers. Bring a picnic. Call John Blake at 291-5079 for information.

July 17. Montgomery County's "Summer Festival of the Arts" hails local folk with a day-long party of band concerts, art shows, folk dancing, crafts, drama and choral concerts. And there are special children's activities, too. Watch local newspapers in July for location and details.

July 29-31. "39th Annual National Folk Festival" brings "300 of the nation's best folk artists" to Wolf Trap Farm for the Performing Arts in Vienna for America's oldest multi-ethnic festival. Says festival director Joe Wilson, "These are honest-to-God traditional people who play the music of their family or community." Five stages will hold groups of various musical persuasions: blues, tex-mex, old-time, country, gospel, balladeers, bluegrass, Ukranian, Cajun and Arabic. Bring your own instruments and jam. Call National Council for the Traditional Arts, 296-0068, for specific information.Call Wolf Trap, 938-3800, for tickets.

July 30-31. "Spanish Heritage Day" caps the District's observation of Hispanic-American Week which ends July 31. Latin musical groups, dancers, artists and community-issues workshops will be based both days in Kalorama Park, Kalorama and Columbia Roads NW.Call 667-0417 for information.

August 11-13. "42nd Old Fiddlers Convention" in Galax, Virginia, draws about 25,000 visitors annually, half of whom come to jam with one another.It's a doozie. Admission charged; camping available. For information, call Oscar Hall at 703/236-6355 or write him at 328-A Kenbrook Dr., Galax, Va. 24333.

August 14. The 1864 Battle of Fort Stevens is re-enacted by soldiers dressed in Civil War uniforms at 2 p.m. in Fort Ward Park, 4301 W. Braddock Rd., Alexandria. A "living history demonstration" precedes the battle. Free. Call 750-6425 for information.

August 16. The rousing "1812 Overture" is performed by the U.S. Army band in an evening performance at the Washington Monument Grounds. Call The National Park Service's "Dial-a-park" for details, 426-6975.