Confession: I do libraries.

I just like 'em. People soak into books, and something of every reader lives on within the covers. You're never alone in a library.

This is the Local History wing of the Central Library, Surrey Street. The ghosts here are more real than most of the people I know. Old friends are watching from their shelf-eyries. Take them down, caress them, tumble into the world they came from.

Let yourself go, and it's 1862, in the thrall of Pawson and Brailsford's eccentric tome, the Illustrated Sheffield Guide. I've browsed this book before, and I'm supposed to be looking for something worthy among its pages. I stifle a yawn, and turn over a couple at once. It's at moments like this, when your guard's down, that a book will strike.

Suddenly this is the junction of Portland Street and Infirmary Road. See this huge two-storey Victorian quadrangle? The smokestacks that surround it are acrid, but the reek of this place is cloying and sweet.

You know, I used to be scared of Bertie when I was a kid. He was some kind of psychedelic golem to me, but he belongs to the future now. It will be forty-odd years before a clumsy representative trips and jumbles his tray of samples, and an imaginative retailer asks whether they can be ordered mixed like that.

There are a hundred and fifty people here. For most of them, life is hard. For ten hours a day, six days a week, life is surreal as well.

In the lozenge hall, they are grinding lump-sugar in a steam mill. Soon they will sift it with the dressing machine, and heave it in sacks through to the mixing room. There their peers will pound in the gum arabic, plus a third ingredient. It could be peppermint-oil. Depending on which of the multifarious range of lozenges they're making at the moment, it could be lemon, or rose, or ginger, or blackcurrant, or tamarind, or ipecacuanha, or opium. They spread the paste onto blocks with outlandish pallet-knives, they roll it two-handed with immense pins, they take up bright steel pattern cutters and they knock out the lozenges in clattering showers. The place is all sanorous clamour and heady scents. Drink it all in, tripping lightly in your spice-heightened consciousness.

Things are looking up for the people of this city. Based on data from its first census in 1841, the average age at death of Sheffielders was then twenty-four years. Today, twenty years on, it's pushing thirty.

Welcome to the licorice department. It takes practice and brawn to heft a spadeful of this sticky black gum, and to slap it down onto the slab. The extract is carted in, in huge black blocks. They strip off the rind with rakes, and sling it by crane into the steam pan, where it bumps and boils for a day, until sterile. Then the crane once again bears it aloft, rising through the floor of this stifling room. The shovels plunge into the soft mass, and once on the slab it's sliced and rolled into Spanish juice-sticks, or moulded into Pontefract cakes, or it's stuffed in slugs into the glistening brass cylinder, from which hissing pistons extrude it through dies into writhing pipes.

Willy Wonka is alive and well in the north of Sheffield. Dahl, of course, loves to draw his characters grotesque and cruel. With the sweet-man, though, he doesn't even come close to the reality.

The comfit-room is a mad-house. The air rings with the screaming of leather belts, as line-shafts in the roof drive twenty revolving copper pans, ridiculous burnished cement-mixers into which liquid sugar slowly drizzles in a continuous stream from gutters along the walls. Sweating men pour in caraway seeds and almonds, and periodically spoon out the congealed syrup into trays. If the ingredient proportions, speed and temperature are just right, the balls do not coalesce, and are of the perfect eating size. Whoever invented the process must have been quite deranged. What with the moustachioed men, in their waistcoats and pill-box caps, and the ridiculous, busy machinery, you half-expect a yellow submarine to sail by at any moment.

When you walk out of here, it will be dark. The sky will be black and starless, and the canyon walls of the tenements will be black, and the rats in the gutters will be black. Black, black, black; as black as the lives of these poor souls is black.

Bassett's factory goes on for ever. You float through the jujube rooms and pastille rooms, still high and haunted, and you alight among the sugar candy, stacked to the roof on pallets. They actually make this stuff in its tin. The boxes are pierced at the ends with a pattern of holes, and threads are passed through so that hundreds of tins are suspended in a kind of web, spanning the room next door. The liquid sugar is ladled in, and the whole assembly is borne into the stove and baked for a day and a night. Left to cool for a full week, the sugar condenses and crystallises on the threads, and the tin is magically filled with sticks of sugar candy, in pink, or yellow, or white. They are clipped at each end, and lidded, and stacked on the pallets.

Outside in the city, things are getting rough. Spice-making is one of the better jobs, really. The buffers and grinders, cooped in the Mesters' workshops among the knives and edge-tools, are caking their lungs with every breath. Trades Unions? Not for another thirty years at least. In the meantime, the workers are sometimes more dangerous than their employers, beating and robbing those peers who are prepared to put up with the degradation and danger of the Victorian workplace. Rattening, they call this crime of surrender for the promise of a crust. Nose to grindstone can be horribly literal in the streets beyond this factory.

The candied lemons are more benign. Three thousand cases of the fruit are stored here at a time. You can spend a lifetime doing nothing but slicing them in two, that and placing the halves on the dies of strange wooden machines, like enormous nutcrackers, that squeeze out the juice and compact the rinds. The liquor drains through a sluice in the wall, straight into the lemonade factory next door. The rind-mass is scraped up, layered around a spike like monstrous doner-dicing in reverse, and pressed into casks filled with brine. In a few months time, they will wash it all clean to rid it of the salt, and boil the cake and pour in sugar, and simmer it all for three days before spreading the fibrous paste into trays for roasting. The pieces are separated by hand, and set in racks for dipping into boiling sugar. Once cooled, they can be boxed and dispatched.

The safety record here is really rather good by contemporary standards. Severed fingers turning up among the candies can be very bad for sales, and so efforts to reduce the incidence of such accidents is sound common sense. Likewise immersions in vats of boiling sugar are detrimental to the application of the remaining workers. The last five years have seen a steady decline in all kinds of these misfortunes, excepting of course the steam boiler explosion that demolished a number of houses opposite.

Messrs Pawson and Brailford find the manufacture of acid-drops to be especially interesting. At one end of the hall, a furnace rumbles away, and above each of its four grates a copper pan full of sugared water is bubbling. The attendants decant in cochineal or saffron, and the pans are then tippled so that their contents sluice onto stone tables coated in butter, on the surface of which the seething liquid will quickly set. A man with a scythe peels the slab off, and folds it, and another man pounds in tartaric acid. Scythed into slices, the material is carried to the mill where the rolls of a mangle revolve under steam. The surface of these rolls is indented with a mesh of drop-shapes, and the sweets pour from the other side into an iron tray dusted with caster sugar. Tomorrow they will make barley sugars instead, or something else, omitting the tartaric acid and substituting jargonelle pear, orange, rose, raspberry, or whatever the fashion demands.

The ledger records a satisfactory week, with 9,767 lbs of goods dispatched, and revenues of £447 13s 1d secured. A profitable and well-run business, and one which hardly ever poisons its customers. It is this fact, it seems, that the proprietors wish to particularly impress upon the compilers of the Illustrated Sheffield Guide, and which sets them apart from their less salubrious competitors.

The librarian is fidgetting. Most of the lights are already out. A twenty-first century winter's evening is waiting beyond the varnished door. I'll be back again soon, maybe to get some real work done, or maybe to take a look where the time-machine is heading next.