Glasgow's domestic time machine. The Tenement wafts you back to the cluttered gentility of 1910 - thanks to a woman who never threw anything away

Climb the stone stairs one floor up. Ring the old-fashioned pull bell by the door of the flat on the right.

As the door opens, a smell - evocative rather than unpleasant, a mixture perhaps of gas lamps, furniture oil, and linoleum - greets you. Not a modern smell, this. Walk through the small dark hall with its oil portrait of a Victorian gentleman, its grandfather clock, and its overfilled umbrella stand ... and into the kitchen. Over to the far corner. There, on some small shelves, stand clusters of earthenware pots and glass jars. They contain jam, mostly homemade.

Nothing unusual about that, you might think. But this jam is rather old. One pot, labeled ``plum,'' is even dated 1929. Why is it still here, uneaten?

``Well, there's a nice distinction,'' Lorna Hepburn explains in her quiet, humorous Scottish voice, ``between keeping a thing and not throwing it away.''

Ms. Hepburn doesn't actually live here. In fact, nobody does anymore. Instead, thousands of people from all over the world come to see this five-room flat.

It is now called the Tenement House. The National Trust for Scotland owns it. After a small amount of restoration, the trust opened it to the public in 1983. Hepburn is its young curator.

Visitors come, and they linger, fascinated. The Tenement House - a typical late 19th-century Glasgow home, one of 56 in a long, characteristic red-sandstone, four-story block in the Scottish city's west end - is not large. It is genteel rather than pretentious. It is filled with ordinary things. But people stay and look round it for hours on end. For some it simply sums up ``all our yesterdays.'' For other, younger visitors, it reminds them of their granny's house, or even seems an entirely unfamiliar, lost world.

In essence, this flat has remained unchanged since 1910. Jam, to say the least, was not the only thing its owner, Agnes Toward (sounds like ``towered''), declined to throw away. For 54 years this unmarried shorthand typist lived here - first with her mother and afterward alone, keeping and caring for everything. She was of a generation that simply expected things to last. This, considered from the standpoint of the chuck-it-out 1980s, is what seems most extraordinary about her home. She changed nothing - from the original wallpaper and lace curtains to the straw mattresses on the beds, the tea caddy above the old black iron range, the fixed wringer by the sink, the carpet beater hanging behind the door, the brass plug for the deep but surprisingly narrow bath.

Miss Toward kept beautiful old hairbrushes, iron kettles, jelly molds, the flour sieve, the kitchen scales with their pyramid of round weights, the meat safe, the Co-op milk can, and even a novelty Pear's soap in the form of a cricket ball. She kept the enamel bread bin, the zinc washboard, the horsehair armchairs, the old flatirons, the 1860s American sewing machine, the red chenille cover for the oval tea table in the parlour, and her gas mask from World War II.

Almost the only concession to ``today'' that she made - shortly before she had to be looked after in hospital for her last 10 years - was to have electric lights installed instead of gas. The National Trust has replaced these with gas again.

Lorna Hepburn thinks that Toward was not at all unusual to believe that ``you didn't just throw things away for the sake of throwing them away.... What is unusual is that things haven't been thrown out afterwards.''

Most homes of older people like this are cleared by the relatives after they go. Toward apparently had none living. She did, however, leave six chairs to a friend, S.L. Davidson, who was an elder of her church. After she passed on in 1975 at the age of 89, he came to her flat with his niece, Anna Davidson, an actress. The place had been unoccupied for 10 years. It was thick with dust. Miss Davidson said she ``felt like Pip in the film version of `Great Expectations,' when he stood at the door of the room Miss Faversham had occupied as a recluse for so many years.''

Dr. Davidson decided the flat just had to be preserved. She bought it (Toward, like everyone else in Glasgow's tenements until very recently, had rented it), lived in it, cleaned it up, and did her utmost to protect everything. She sold it to the National Trust when she left Glasgow.

The trust painted the walls to closely replicate the original wallpapers; had their blacksmith repair the range, which had been damaged by a hammer-happy plumber; and added a minimum number of things - ornaments on the parlor mantelpiece, for example, a few Victorian prints on the walls - to underline the period. But the majority of objects, cannily displayed so that the flat looks lived in and as little as possible like a museum, were Toward's.

The good lady would doubtless be astonished that parties of schoolchildren come through and sketch her piano. They ask questions about the bed in the kitchen and inspect the spiders in the bath (one child thought they must be 100 years old like everything else). And they speculate about the function of that hefty iron object with dials on the shelf in the bathroom. One small boy thought it was an instrument designed to tell you how long you had been in the bath. Actually, it is a Victorian gas meter.

Beyond Toward's lace curtains, Glasgow has changed even more amazingly. The tenements of poorer quality that used to be opposite her parlor window have been torn down. Small, rather garish red-brick houses have replaced them. And a motorway, thundering continuously with traffic, has been built just beyond.

``Yes,'' muses Hepburn, ``she would have had a lot less noise. And a lot more dirt.''