A working-class family of a century ago might have found the idea puzzling, but yesterday's grim textile sweatshops and once-hazardous coal mines are being transformed into today's popular tourist attractions. Many of us, it appears, take a macabre fascination in observing how unpleasant it sometimes was to live -- and to work -- in the really bad old days of decades past.

This doesn't mean, of course, that a glimpse of the harsh working conditions of another era is the only reason to visit these places. They provide an absorbing and educational look at how our grandparents and great-grandparents earned a living using simple tools and muscle power to accomplish tasks now assigned to high-tech gadgets. And certainly there's inspiration in learning something of the amazing ingenuity of America's early inventors.

Across the country, sites where bygone generations toiled long and hard are preserved as museums, some quite intriguing and even fun. They are, in one sense, tributes to the accomplishments of working men and women -- and to the nation's industrial genius. But they also are often very graphic reminders, as we celebrate Labor Day, of the wage-earner's long, uphill struggle for decent pay, shorter hours and safer working conditions.

One of the most interesting and saddest stories -- it has a happy beginning and an unhappy ending -- is told of the thousands of young women from New England farms who in the early 1800s helped launch the American industrial revolution as "mill girls" in the booming textile factories of Lowell, Mass.

At the outset, the women eagerly tended their looms for 12 hours a day for what at the time was considered good pay -- better even than a teacher made (although about half of what a male mill worker might earn). Later, the factory owners began to lengthen the already long hours, increase the workload and at the same time cut pay. And they got away with it, although many of the women put up a fight. Ultimately, the owners replaced the "mill girls" with immigrant laborers whom they could get for even less.

You can learn about the life of the "mill girls" and of the immigrants who followed them -- the Irish, the French-Canadians, the Greeks, the Poles -- at the Lowell National Historical Park, a nine-year-old museum park that now occupies several former textile factories in the heart of old Lowell, about an hour's drive northwest of Boston.

A visit to a mill complex may sound gloomy and unappealing, but the free ranger-guided tours are quite the opposite. For 2 1/4 lively hours -- the longest and the best of the tours -- you explore Lowell's one-time industrial grandeur by foot, restored electric trolley and open motor barge. On two occasions, the barge negotiates the old locks on Lowell's 5.6 miles of hand-dug and still functioning canals. "Keep your arms and elbows inside," warns the ranger, and the barge rises with the inflowing water.

Elsewhere in the country, Labor Day celebrants -- or anyone interested in how their forebears earned a living -- can choose from a variety of occupation-related museums or restored work sites celebrating everyday workers and their accomplishments.

You can, for example, ride an underground railway deep into the Lackawanna Coal Mine in Scranton, Pa.; stroll the streets of Eckley Miners' Village, a Pennsylvania historical museum; step back into a farm of the 1870s at Agrirama, Georgia's official Museum of Agriculture in Tifton; see firsthand the rugged life of a ranch hand at the Grant-Kohrs Ranch National Historic Site in Deer Lodge, Mont.; and watch glassmaking in Wheaton Village, a restored 1880s glass-manufacturing town in southern New Jersey.

In the eyes of its founders, Lowell, officially named in 1826, began as an ideal factory town -- America's first planned industrial community. The mill owners, with good intentions, wanted to avoid the squalid working conditions that already were a scandal in Great Britain's factories. Unfortunately, in the second half of the 19th century Lowell descended to what the Park Service describes as "a city based on the exploitation of a permanent working class."

At first the owners recruited young New England farm women -- a reliable, hard-working source of labor -- and provided them with respectable accommodations in well-supervised company boardinghouses. In their off hours, the women, ages 15 to about 30, were encouraged to improve their lives by attending concerts and lectures. Many of them welcomed the opportunity for factory work as a way to earn money for their dowries or to support the family back home. For some, it was a rare chance to become independent.

Lowell flourished at the start -- the "Eldorado on the Merrimack," it was dubbed -- and travelers and scholars came from afar to witness its significant industrial achievements and to praise the treatment of its labor force. In a decade, the tiny farm village grew to a city of 17,000 -- America's first great industrial center -- where eight major mills employed 7,500 workers, most of them raised on farms.

On a bright summer morning, ranger Becky Warren -- a Yankee "farm girl" herself, she says -- gathers her small tour group around to recount the story of the "mill girls" and of Lowell's rise as an industrial power, its subsequent disastrous fall and -- in recent years -- its reemergence both as a prospering computer products center and an agreeable tourist destination.

In its heyday in the mid-19th century, says Warren, Lowell's many factories wove more than 2 million yards of cotton cloth a week. Now all the textile factories, except for a few working with synthetics, are gone. In view behind Warren as she speaks are several of the huge red-brick buildings that make up the historic area, including the long, five-story structure that serves as the park's visitor center. Many mill buildings had badly deteriorated before restoration work began.

"When I was growing up," recalls Warren, "I was embarrassed to say I lived near Lowell." Now she is proud of the city's obvious resurgence and of the new attention being paid to its historical significance.

The Mill and Canal Tour -- the 2 1/4-hour one -- begins in a flower-adorned courtyard just outside the visitor center. The structure was built in 1882 as a carpet-making plant but was abandoned in the 1920s when Lowell's textile companies began moving to the South in search of cheaper labor. Its restoration five years ago was a major part of Lowell's revitalization.

The center overlooks the Merrimack Canal, one of the city's primary industrial waterways. Lowell was chosen as a major factory site, explains Warren, because of the abundant water provided by the Merrimack River, which tumbles down rock-strewn Pawtucket Falls on the edge of Lowell. The canals channeled the water to the factories and also provided a boating route around the falls. Appropriately dominating the courtyard is a full-size statue of a muscular 19th-century laborer at work dredging a canal.

Lowell was named for Boston merchant Francis Cabot Lowell, who back in 1811 had a chance to tour textile factories in England and Scotland. Cleverly memorizing the advanced technology in use, he returned home with enough information to have the power looms quickly duplicated. He was, says Warren, "our first industrial spy."

Pondering that historical curiosity, we board the 32-passenger electric trolley, a replica of the kind that at the turn of the century carried workers to the factory or into the countryside for Sunday picnics. A conductor in Victorian garb toots the whistle and a flagman runs ahead to halt intersecting traffic. Our destination is Suffolk Mill, a restored factory structure that now houses commercial offices. On its first floor, however, is an operating water turbine, one of the many that once ran Lowell's factories. It is now operated as an exhibit on the uses of water power.

Warren ushers us inside a large room where once 166 looms clanged noisely. "Mill girls" spent 12 hours a day -- and eight on Saturdays -- seeing to it that the looms ran smoothly and profitably. The room, we quickly discover, is hot and very stuffy -- "like a sauna," says Warren -- the same sort of conditions the women worked in. The high humidity increased the moisture content of the cotton strands and prevented them from breaking easily.

All the mill windows were nailed shut -- they provided light, not ventilation, Warren says -- and cotton lint filled the air. Many of the women suffered lung damage as a result, and others lost their hearing because of the noise.

We peer at the turbine, kept spinning by water flowing from the canal alongside the mill. Warren pulls various levers to demonstrate how this huge hunk of metal, linked to wheels and wide leather belts, powered the looms. Even to someone not mechanically inclined, her explanation proves surprisingly interesting, perhaps because she doesn't forget the tragic human element in this early technological marvel. It seems the exposed, high-speed belts -- one at each loom -- presented a special hazard to the women. If their hair got caught, as it sometimes did, they might be scalped instantaneously. We shudder at the horror and steer clear of the belt.

Only one loom currently is on display at the Suffolk Mill, but by the spring of 1989 the park expects to open the Boott Mills Museum nearby, a major expansion of its exhibit area. At Boott Mills, 100 operating power looms will fill an authentically re-created weave room. By next February, the park also plans to have restored an 1835 boardinghouse, depicting the everyday life of a "mill girl." Downstairs will be the parlor and dining room where the boarders ate three hot meals a day. Upstairs will be the dorms. Typically, four women shared a bedroom -- usually two to a bed. For this, they paid up to half their weekly income.

On we proceed through Lowell's industrial past, this time by motorized barge, skirting the city's modern commercial heart. Our first stop is a hand-operated canal lock, where our vessel is raised three feet in its climb toward Pawtucket Falls. Next stop is the Pawtucket Gatehouse and a good look at the falls, more a splash of white-water rapids than a plummeting stream. The gatehouse bears a plaque designating it as a National Historic Mechanical Engineering Landmark. A wonder of its day, the gatehouse is the intake point for the water that flows in Lowell's canals.

We board a second barge now, this time for a trip along Lowell's oldest canal, dug by local farmers as a way around the falls for New Hampshire timber being sent to shipbuilders on the Massachusetts coast. "Watch the perfect dive," shout two youngsters, plunging from an old railroad bridge moments after we pass under. They are a snapshot from another century.

On our left, just before we dock, is Joan Fabrics, one of the few textile firms operating in Lowell. It makes car seat and furniture upholstery. Once more we board an electric trolley, heading back from our wide circle tour to the visitor center as Warren concludes her story.

At first, the young women who came to Lowell "were very happy," says Warren. They stayed usually for three or four years until they had saved sufficient money. Many wrote home about their pleasant life, although others found the work tedious and resented the mill bells that summoned them to work.

Other textile mills sprung up elsewhere in New England, however, and the Lowell factories faced heavy competition. Their move to increase hours and cut pay -- rather than trim investors' dividends -- prompted Lowell's first strike in 1834, which was unsuccessful. By the 1840s, many "mill girls" had become disillusioned, and they returned home or went elsewhere. The immigrants, desperate for work, snapped up the jobs. Overcrowded tenements soon replaced the boardinghouses, and labor and management strife erupted in the early 1900s. The Park Service plans to open a large new exhibit on Lowell's immigrant factory workers and their families in February.

A 15-minute slide show at the visitor center adds this epilogue: By the end of World War I, competition from more modern textile factories in the South and a cheaper labor source persuaded the owners of Lowell's mills to close down or open new plants in the South. Says the Park Service: "Lowell slid into decades of economic decline."

Not until the 1960s did the city wake up to a much brighter future. The spur was a combination of private and public efforts aimed at protecting Lowell's heritage and honoring its pioneering role in America's industrialization. Today Lowell is a symbol, says the Park Service, both of "the triumphs and the tragedies of American industry."

We end our visit lunching in a shady courtyard on Greek gyro sandwiches, sold at the visitor center's collection of excellent ethnic fast-food shops called the Melting Pot. By good fortune, a group of folk singers and musicians -- part of a summer cultural series -- is entertaining with foot-tapping Irish tunes -- and, the perfect touch to the day, what sounds like a rousing union solidarity song or two.

Among the country's other labor-related historical sites and museums:

Lackawanna Coal Mine, Scranton, Pa.: In the first half of this century, Scranton's vast anthracite coal mines provided the fuel that heated much of Washington and other big cities of the East Coast. By the 1960s, however, the demand for coal had so diminished that now the industry is all but dead in the Scranton area.

As a way to preserve the region's mining heritage, Lackawanna County recently opened one of the former mines for hour-long guided tours. Visitors board a miner's rail car to descend about one-fifth of a mile into a sloped tunnel. There, 100 yards below the surface, a former mine worker leads the group through mine passages and chambers, explaining the coal-mining process and providing a glimpse of a miner's sometimes hard and dangerous life.

Workers took coal from the mine from the turn of the century until 1966, according to spokesman Bill Risse, and in the early years they had to work six days a week. If a coal vein ran close to the ground, a miner might spend much of his life on his hands and knees getting at it. When the guide points out one of these "low coal" areas, says Risse, "it brings peoples' hearts into their throats."

In Scranton, "Just about everybody's grandparents had something to do with coal," says Risse. The mines drew large numbers of immigrant workers -- Irish, Italians, Greeks, Russians -- who continue to celebrate their origins in frequent ethnic festivals in the city.

The mines also prompted two other local industries -- the manufacture of railway steam engines and silk weaving. Coal provided convenient fuel to build the massive engines, and this aspect of Scranton's history is on display at Steamtown, USA, a major museum collection of steam engines.

Silk weaving as a Scranton industry reveals the tragic side of coal mining, for weaving mostly was the work, says Risse, of wives of disabled miners or of widows of men killed in the mines. Needing an alternate income, they were a source of cheap labor for the local silk mills. Their story and that of Scranton in the coal age is told in the Pennsylvania Anthracite Heritage Museum, located across from the Lackawanna Coal Mine.

To round out a look at coal miners and their lives, drive about an hour south of Scranton to the Eckley Miners' Village near Hazleton. It is a restored mining village dating from the 1850s. The village, a part of the state anthracite museum complex, portrays the life of a miner and his family.

Agrirama, Tifton, Ga.: The name suggests a futuristic exhibit at Disney World's Epcot Center, but Agrirama is, in fact, a pair of re-created Georgia farmsteads of the 1870s and 1890s. There's also a reproduction of a small farm town. Officially, the complex is Georgia's Agricultural Heritage Center.

Visitors to the 93-acre museum, about 175 miles south of Atlanta (or 215 miles north of Disney World), explore the farms and the town buildings -- a gristmill and a sawmill, for example -- watching costumed interpreters perform the farm tasks of a century ago. Since the center is open year-round, these tasks have a seasonal theme. Invariably, they require a substantial amount of individual labor.

In late May, turpentine is made from pine rosin in a wood-fire still -- the way Georgia farmers did it in the past. New cotton is ginned in October. And in November sugar cane is ground for syrup making. Often there are displays of soap making and quilt making. And you can watch the fields being plowed -- with a slow, mule-drawn plow. The mule pulls but the farmer guiding the plow works just as hard.

Wheaton Village, Millville, N.J.: For more than a century, southern New Jersey has been a center of glassmaking, taking advantage of the plentiful supply of silica sand that is a major ingredient of glass. Like other factory areas, this part of the state attracted immigrants -- Italians and Germans -- in search of work.

Wheaton Village is a re-created glass-manufacturing town of the 1880s, named after pharmacist T.C. Wheaton who went into the medicine-bottle manufacturing business in Millville in the 1880s. The Wheaton Glass Co., adjacent to Wheaton Village, still makes bottles for pharmaceuticals and cosmetics, employing about 1,500 workers in its Millville plant.

Victorian in style, Wheaton Village sits on 88 acres shaded by tall pines. The "promenade" is lined by craft shops of the period where artisans such as a tinsmith and pottery maker are at work. A Victorian-style soda fountain features ice-cream treats.

The highlight of the village is the 1888 glass factory, where visitors can watch glassmakers at work, creating both functional objects -- a Victorian water pitcher -- and creative artworks, often in the style of the 1880s but in contemporary patterns as well. Some of the glasswork made at Wheaton Village is sold to visitors.

Grant-Kohrs Ranch National Historic Site, Deer Lodge, Mont.: A wide expanse of rolling hills in the shadow of the Rocky Mountains, Grant-Kohrs once was one of Montana's largest ranches, grazing cattle on more than a million acres. Still a working ranch, but reduced to a 260-acre park, it commemorates America's frontier cattle-ranching era of the 1860s.

Life on a 19th-century ranch is depicted in a number of original ranch buildings that include the 23-room main house, begun in 1862, and the bunkhouse (even older) where the ranch's full-time hired hands shared a bunk room filled with metal cots. Park rangers lead guided tours through the main house, and visitors can explore the other structures with an informational map in hand.

Throughout the year, ranch hands are at work, tackling seasonal chores with tools from the past century. After the early summer roundup, cattle must be branded, an event for the nonsqueamish usually held on a weekend in July. At other times in the summer, workers cut hay using a horse-drawn mower. Afterward, the hay is rolled into piles and stacked with an antique hay stacker.

Other tasks are more routine: mending fences, shoeing horses, whitewashing the ranch buildings.

A ranch the size of Grant-Kohrs at its peak might have kept eight ranch hands busy year-round, and another 100 might have been taken on in the summer for haying and to help in the roundup. Often a chuck wagon accompanied them into the hills. Nowadays, summer visitors can watch a chuck wagon cook at work on weekends -- and even sample some traditional campfire beans, biscuits and black coffee.