John Lentz sat atop the big rock that separates the ieft chute from the middle chute in turbulent Difficult Run, reminiscing about the time he rescued the arm in the jacket.

"It was only the second time I took Judy (now his wife) out on the river We were having lunch over there," he said, pointing to a sandy strip along the Maryland shore.

"I heard this tremendous 'clang,' of aluminum hitting rock, and I knew there was nothing there to hit unless you were way off course. Somebody was in deep trouble."

Lentz left behind his courtship and crumpets, jumped in his canoe and paddled out in the white water.

"The first thing I saw was the canoe and a kid holding onto it. I asked him if he was okay and he said yes, but he didn't know where his partner was.

"I looked upstream and saw this arm, tangled in a life jacket, tearing down through the rapids. I paddled (to the spot) and stuck a hand down and managed to pull him in the boat, sputtering and coughing.

It turned out the youngsters were with a Boy Scout troop that was doing a river adventrue. Lentz remembered seeing the troop leader going downstream at the head of the pack "waving his paddle in the air like it was some kind of joy ride."

The fast water of the Potomac from Great Falls to Little Falls can be a joy ride all right, but if you don't know your stuff it can be your last one.

Lentz, who has learned this stretch as well as anyone in 17 years of paddling it, led a three-boat contingent down the spring-high waters on Sunday for a look at how to do it properly.

We started at the Great Falls park on the Maryland side, six strange figures toting open canoes on our heads while a pack of juvenile "bearers" carried our life jackets, lunches and paddles.

The loaded-down hike to the water alone is a test of one's mettle - a long flat span on the towpath, then a half-mile of craggy Billygoat Trail to the Potomac's spillway below the Great Falls.

Lentz, who has a weightlifter's chest and shoulders pinned on a marathoner's narrow legs, started us off in the water with a quick lesson on strokes. Then we were off, almost immediately taking water over the bow in the first stretch of curlers.

"Nice level," said the amussed Lentz, who promptly decided that before the next fast water his hefty bow man would move back amidships.

This is nicely balanced sport, whitewater canoeing. Each rush of fast water induces an adrenalin surge and an infusion of thrills and scares. Then there is a mile or so of serene flat water to collect thoughts and soak in the slow-moving scenery.

Each set of rapids announces itself first with a distant burbling, then the steadily increasing roar of rocks and water. It't time to start thinking fast.

The seven-mile run from Great Falls to Sycamore Island that Lentz took us on is the same stretch Canoe Cruisers Association racers will do two weeks hence in the club's annual Potomac bash.

They will pick their way through Yellow Falls and Difficult Run, Wet Bottom chute and the Stublefield Falls.

But they'll be racing and won't have time along the way to enjoy the river scenes we marveled at on this sunny spring day.

The mad bicyclist/frisbee-er/rock climber who decided to combine his sports. We watched him lowering his frisbee-bedecked 10-speed down the rocks to the Mather Gorge. Why? Who knows.

People aged 55 and over owned 69 percent of the land in the county while 63 percent of the owners were 45 and over.

Wonderlich found that real estate is the "primary industry of the county," with land sales exceeding the vaue of retail, agricultural or other sales.

The mad musician who pranced down a sheer rock face with a delicate and expensive Martin guitar under his arm so he could do a sound battle with the raging Potomac. I don't think he could even hear himself.

The lady who responded to our query, "Catching any fish," by lifting her rod tip and finding a very healthy white perch at the end of her line.

The kayakers who play like dragonflies on the heaviest rapids, pointing their bows upstream and watching the frothy water pound over and under them, sneaking upstream in the eddies and then swirling around and riding the thunderous current down again.

The world's dumbest Canada goose, who took offense at the arrival of Dave and Maury Halsey's 18-foot Grumman, hissed and paddled straight for them, stopping five feet away. I'd like to meet him on the Eastern Shore next fall.

The Rip Van Winkle at Offutt's Island who didn't wake up when we rammed the rock he was passed out on. "Maybe we should have poked him or something, to see if he was alive," said Lentz. But I checked. He was breathing.