By George Ridge

MARFA, TEXAS, USA - Have you seen the Marfa Lights?

Ask this question randomly north of the Big Bend in Texas -- an area about the size of Spain-- and 8 of 10 people will not only answer ''yes, sir!'', but they will offer an enthusiastic description.

Other than the movie ''Giant,'' which was filmed nearby, Marfa's worldwide claim to fame lies on the sage-covered desert east of town, where mysterious nocturnal lights have baffled residents and scientists since the first settlers arrived in 1883.

''Yes, sir!'' answered a woman carrying her groceries out of what passes for a supermarket in Marfa. ''Only two people I know of around here haven't seen the lights.''

Exactly what do the Marfa Lights do?

''Oh, I've seen them in a mating dance,'' she allowed. ''That's when one stands still and three of them dance around it. I've personally only seen white lights. But some folks see red, blue, yellow. They bounce all around and sometimes even chase you. Whatever they feel like doing, they do! If you sit long enough, they really get with it.''

One local publication advertises ''The Marfa Lights on Videotape'' for $10, plus $1.50 postage. Assuming you want to stalk Marfa Lights in the wild and not on a VCR, how does one go about it?

''Drive about nine miles toward Alpine on Highway 90,'' advised Sandy at the Chamber of Commerce.

''There's a parking turnoff. You can't miss it. Get there about 10 minutes before complete darkness. They're most active then. Look south. Some people have seen them north of the highway, but mostly they appear near a mountain called 'Twin Peaks.' That mountain kinda looks like Dolly Parton, if you know what I mean.''

To the great joy of the Chamber of Commerce, Marfa's lights have ''never done anything bad.'' A favorite local story concerns a professor at Sul Ross University who became lost on a hike near Twin Peaks. After searching several hours for his pickup truck, he was preparing to spend a shivering, fearful night in the desert when a light appeared about a mile away. Thinking it was a ranch, he headed in that direction. The light was hovering just to the side of his truck. It flicked out as he saw the vehicle.

''Some people say these are just jackrabbits with flashlights, but that was no jackrabbit that found that pickup!'' emphasized Sandy. ''We had 40 Japanese scientists come here for six weeks. They never found the reason for the lights.''

I uncovered only one person who had not seen the lights. ''Nope. Never seen the Marfa lights," snapped a Sul Ross student who was tending bar at the local ''private club'' in Fort Davis. "But," she added with a softening of tone and conspiratorial air, "I've sure seen the glowing gravestones of Van Horn.''

As a geology student, our bartender had a down-to-earth explanation for the Van Horn gravestones. ''There are flecks in the granite out here that hold phospheresence. The gravestones pick up headlights or flashlights and glow after the light is extinguished.''

A customer at the bar turned on her in fury. ''Then how do you explain the glowing gravestones at Fort Davis! There's no headlights out there!''

The geologist-publican shook her head. ''Got me on that one,'' she shrugged.

Tourism Tip

For a ghostly experience even if you don't see the Marfa lights or the glowing gravestones, stop by Fort Davis. It was built to protect the stagecoaches and settlers.

At 4 p.m. daily, as the summer thunder echoes like distant cannon under squall lines across West Texas, the National Park Service plays a recording of a cavalry retreat ceremony. The broad, deserted parade ground at Fort Davis contains phantoms of many campaigns as the unseen adjutant on the public address system receives reports from equally invisible first sargeants. The evening gun booms, Old Glory is lowered and the commander orders the evening review ''forrard.''

To the strains of ''Garryowen,'' those who in their own time occupied Fort Davis until 1891, pass in the mind's eye: the 9th and 10th U.S. Cavalry of Buffalo soldiers, troopers of the war with Mexico that included Robert E. Lee, the Confederates, the immigrant wagons and the Commanches, undoubtedly watching sadly from a ring of granite bluffs.

For more great ideas of things to do in Texas, check out Food Festivals of Texas: A Traveler's Guide & Cookbook.