August is the cruelest month for those of us left behind in Washington. Although not so hot and humid this year, August is humdrum. (Particularly when we know friends and coworkers are reveling in other climes.)

For those of you down in the dumps about being around, here are 10 oases to boost your spirits: free, accessible and refreshing in-town escapes, even on your noon hour. You may even come back with a suntan. DUMBARTON OAKS

This Georgetown mansion belonging to Harvard University -- where scholars in landscape architecture, Byzantine and Precolumbian studies reside -- is the escape favorite for many.

The magnificent estate, 1703 32nd St. NW, with its formal gardens of flowers and vegetables, fountains, winding paths and bordering forest is open to the public from 2-5 daily. The collection of Byzantine and Precolumbian art is open 2-5 Tues-Friday.

Pets and picnicking are not allowed, but strolling through is a pleasure, at least once each season of the year. JAMES MADISON MEMORIAL BUILDING

A peaceful and unexpected treat of a retreat hidden away deep within the marble of the new Library of Congress building. Walk past the friendly guard, past the 1980 White House News Photographers Exhibit (spend a few minutes of your escape on this entertaining exhibit), and through the double glass doors. You'll find yourself in a wonderfully cool and tranquil indoor garden court, softly lighted and filled with exotic tropical trees and plants.

Three abstract copper "waterfalls," gone green with time and moisture, gurgle soothing background "music" for private thoughts or for reading a summer novel. Stretch out right next to the fountain and trail your hands in the cool water, or hide behind a tree.

The Madison Building, 101 Independence Ave. SE, is a block from Capitol South Metro. Open 8:30 a.m.-9:30 p.m. Monday-Friday; 8:30 a.m.-5 p.m. Saturday; 1-5 p.m. Sunday. OLD STONE HOUSE

A lovely, quiet public garden smack in the middle of cacophonous Georgetown? You've probably rushed past this M Street oasis countless times on your way to Wisconsin Avenue shops. The historic landmark, once George Washington's headquarters during the Revolutionary War, is a compelling anachronism in the midst of commercialism.

Pass through the garden gate and leave the city behind. You'll find a well-tended garden, lush, soft lawn and shady trees. Remarkably, little of M Street's bleeps and blares penetrate this peaceful escape. A favorite for picnickers, shoppers and couples.

The Old Stone House, 3051 M St. NW, is open Wednesday-Sunday 9:30 a.m.-5 p.m. EASTERN MARKET

A feast for all senses. Take a stroll through the ancient red-brick market building, with its colorful collage of fresh meats and produce, friendly salespeople and customers.

If you forgot to pack a lunch, all the better. Starting in September, you may want to fill a basket with farm-fresh groceries or just grab a sandwich and eat at a table under the outdoor concourse. There you'll find more fruits and veggies, plus an assortment of artists displaying offbeat works. (The neighborhood, with its charming collection of boutiques, plant shops and antique markets is an escape in itself.)

Eastern Market, C and 7th streets SE, is two blocks from the Eastern Market Metro stop. Open Tuesday-Saturday, 8 a.m.-8 p.m. BACK TO SCHOOL

To revive fond memories and make new ones, take a lunchtime college break on one of Washington's beautiful and secluded campuses. During the summer session, a college campus offers a serene setting for a picnic lunch, and when school's in session there are plenty of colorful characters about. American University, Georgetown University and the Catholic University of America are among the better-known campuses; all are accessible by public transportation. MERIDIAN HILL OR MALCOLM X PARK

Definitely seedier than it used to be -- with weeds growing through the cracks and algae lining the fountains -- but still beautiful.

Between the Italianate garden, huge tiered fountain and the bordering Latin neighborhood it takes very little imagination to pretend you're in a foreign country. You may even catch -- as we did -- a family of 10 swimming in the fountain and cooling their beer in the cascading water.

It's wise, however, not to go alone. Even though frequented by picnicking families and old men playing chess and shuffle board, the area has a reputation for crime. So bring a friend and leave the purse at home.

The park at 16th and V streets NW, is available between dawn and dusk, and animals are allowed on leashes. NATIONAL PORTRAIT GALLERY

With its civilized tables, chairs, fountain and ample grass, the kiosk courtyard in the museum is perfect for lunch, whether in a bag or from the gallery's Patent Pending restaurant.

National Portrait Gallery, 8th and F streets NW. Courtyard open between May and December, 11:30-3:30 Monday through Friday, and 11:30-4 on weekends. GARDEN OF THE CHRISTIAN HEURICH MANSION

Located behind the Columbia Historical Society, this small, secluded garden is a pleasant alternative to the heavily used and abused Dupont Circle (about a block away).

Enter a tall, wrought-iron gate on Sunderland Place and discover an English garden with lots of flowers, including a large bed of roses, scattered statues and a few benches. Plenty of shade, though some of it comes from surrounding tall buildings. CHS welcomes visitors bearing brown bags, but asks them to ditch their garbage in a proper dump.

Columbia Historical Society, 1307 New Hampshsire Ave. NW, open during normal business hours during the week, closed on weekends during August. NATIONAL ARBORETUM

Take either a very long lunch or the whole afternoon for this one. Past downtown, the Capitol and down New York Avenue, the Arboretum in Northeast is worth the haul.

Because it's nearly impossible to see everything on one trip, concentrate on a different blooming area each time you go. In the herb garden small plaques beside each bed explain their scientific classification, history and use. While picking the plants is prohibited, smelling is okay. And you might want to try to photograph the foot-long (disgusting) goldfish in the waterlily pond. Leashed animals and picnics welcome here.

The Arboretum, R and 24th streets NE, open 8-4:30 during the week, 10-5 on weekends. TST. THOMAS' ESPICOPAL CHURCH

A quiet, if eerie place steeped in history.

In August 1970, arson destroyed the 71-year-old Gothic building where Franklin Delano Roosevelt prayed. Today, only the bare alter and eastern frame remain of the once-fashionable church, where ushers wore tails. Park trees and benches have replaced the stained-glass windows and pews.

On Sundays, The Rev. Henry Breul still conducts services there. During the week, strangers to the parish stroll through the premises.

St. Thomas' park, 18th and Church streets NW, is cool, shady and open to the public during normal business hours, Monday-Friday.