A velocipede chattered past. They had started to appear on the streets two years ago, these steam-driven, one-man vehicles, and were popularly known as "penny-farthings" due to their odd design, for the front wheel was nearly as tall as a man, while the back wheel was just eighteen inches in diameter.

The rider was seated high on a leather saddle, situated slightly behind the crown of the front wheel, with his feet resting in stirrups to either side, his legs held away from the piston arm and crank which pumped and spun to the left of the axle. The tiny, boxlike engine was attached to the frame behind and below the saddle; the small boiler, with its furnace, was under this, and the coal scuttle under that; the three elements arranged in a segmented arc over the top-rear section of the main wheel. As well as providing the motive power, they were also the machine's centre of gravity and, together with the engine's internal gyroscope, made the vehicle almost impossible to knock over, despite its ungainly appearance.

By far the most remarkable feature of the penny-farthing was its extraordinary efficiency. It could complete a twenty-mile journey in about an hour on just one fist-sized lump of coal. With the furnace able to hold up to four pieces and with the same number stored in the scuttle, it had a maximum range of 160 miles and could operate for about twenty hours before needing to refuel. The vehicle's main flaw, aside from the thorough shaking it meted out to the driver, was that the two slim funnels, which rose up behind the saddle, belched smoke into the miasmal atmosphere of England's capital, adding to an already bad situation. Nevertheless, the vehicles were currently all the rage and had done much to restore the public's faith in the Engineering faction of the Technologist caste, a group that had been much maligned of late after the disastrous flooding of the undersea town of Hydroham off the Norfolk coast, and a number of fatal crashes during the attempted-and ultimately abandoned-development of gas-filled airships.

Burton watched the contraption disappear into the mist.

London had transformed while he'd been in Africa. It had filled with new machines and new breeds of animal. The Engineers and Eugenicists-the main branches of the Technologist caste-seemed unstoppable, despite protests from the Libertines, who felt that art, beauty, and nobility of spirit were more essential than material progress.

The problem was that the Libertines, despite producing reams of anti Technologist propaganda, were unclear in their message. On the one hand, there were the "True Libertines," such as the Pre-Raphaelite Brotherhood, who were basically Luddites; while on the other, there were the increasingly powerful "Rakes," whose interests ran to black magic, anarchy, sexual depravity, drug taking, meddling, and general bad behaviour, which they justified as an attempt to "transcend the limitations of the human condition." Most Libertines, Richard Monckton Milnes being a prime example, fell somewhere between the two camps, being neither as dreamily idealistic as the one faction nor as scandalously self-indulgent as the other.

As for Sir Richard Francis Burton, he wasn't sure where he fitted. Although it was the country of his birth, England had never felt like home, probably because he'd spent most of his childhood being dragged around Europe by his restless parents. He was therefore rather surprised when he returned from the Nile expedition and found that the country's current state of social instability somewhat suited him. The rapid changes, more intensely felt in the capital than elsewhere, might be confusing to the majority of the populace but he'd always regarded his own identity as rather a transient and changeable thing, so now he felt an odd sort of empathy with the fluctuating nature of British culture.

As he walked, he slowly became aware of a tapping noise from somewhere above and realised that he'd been hearing it on and off since leaving the club. He peered up and around but saw nothing.

He continued his trek home, listening, and, yes, there it was again. Was he being followed? He looked back, but there was no suggestion of anyone on his heels until a policeman started to trail along behind him, his attention attracted by the lone, obviously rather drunk man's brutal features. After five minutes or so, the constable drew closer, saw that Burton wore the clothes of a gentleman, hesitated, then abandoned the chase.

The explorer crossed Charing Cross Road and entered a long, badly lit side street. His foot hit a discarded bottle that spun into the gutter with a musical tinkle. Something large flapped overhead and he looked up in time to see a huge Eugenicist-bred swan pass by, dragging a box kite behind it through the mist. A man's white face-an indistinct blur-looked down from the kite before it vanished over the rooftops. A faint voice reached Burton's ears but whatever it was the man had shouted was muffled by the water-laden air.

Last year, Speke and Grant had used the same form of transportation to make their way to the Nyanza, following the old route. It had taken a fraction of the time required by Burton's expedition. They'd set up camp in Kazeh, a small town some hundred and fifty miles south of the great lake, and here John Speke had made one of his characteristic errors of judgement by failing to properly guard his birds. They'd been eaten by lions. Without them he couldn't circumnavigate the lake, couldn't ascertain whether it was the source of the great river, and couldn't prove Burton wrong.

A few yards farther down the road, a man shuffled from the shadows of a doorway. He was a coarse-featured individual clad in canvas trousers and shirt with a rust-coloured waistcoat and a cloth cap. There were fire marks-red welts-on his face and thick forearms caused by hours spent stoking a forge.

"Can I 'elp you, mate?" he growled. "Maybe relieve you of wha'ever loose change is weighin' down yet pockits?"

Burton looked at him.

The man backed away so suddenly that his heels struck the doorstep and he sat down heavily.

"Sorry, fella!" he mumbled. "Mistook you fer somebody else, I did!"

The explorer snorted scornfully and moved on. He entered a network of narrow alleys-dark, dangerous, and sordid-a dismal tentacle of poverty reaching far out of the East End into the centre of the city. Mournful windows gaped from the sides of squalid houses. Inarticulate shouts came from some of them-occasionally the sound of blows, screams, and weeping-but hopeless silence came from most.

It occurred to him that the depths of London felt remarkably similar to the remotest regions of Africa.

He came to a junction, turned left, tripped, and stumbled; his shin banging against a discarded crate and his trouser leg catching on a protruding nail and tearing. He spat out an oath and kicked the crate away. A rat scuttled along the side of the pavement.

Leaning against a lamppost, Burton rubbed his eyes. The taste of brandy burned uncomfortably at the back of his throat. He noticed a flier pasted to the post and read it:

Work disciplines your spirit

Work develops your character

Work strengthens your soul

Do not allow machines to do your work!

Pushing himself away, he walked along the alley and turned yet another corner-he wasn't sure where he was but knew he was proceeding in the right general direction-and found himself at the end of a long, straight lane, its worn cobbles shining beneath the haggard light of a single lamp. It was bordered by high and featureless redbrick walls, the sides of warehouses. The far end opened onto what looked to be a main thoroughfare. He could vaguely see the front of a shop, possibly a butcher's, but when he tried to read the sign over the window, a velocipede clattered past it, leaving a swirling wreath of smoke that further obscured the lettering.