“We’ll drop in on my pharmacist, Mr. Shudders.”

“Why?”

“He supplies me with Saltzmann’s Tincture.”

Swinburne screeched, “What? What? What? The drug Sadhvi Raghavendra has repeatedly warned you against is sold by a man named Shudders—and still you gulp it down? I think you might be the most ridiculous fellow I’ve ever met!”

“That, Algernon, is because, unlike me, you’ve never had the advantage of encountering yourself.”

“But—for crying out loud!—you’re buying more of the foul poison? Your addiction is beyond the bounds! Must I gather the Cannibals and have them help me lock you away until the dependency has passed?”

“I simply want to know where he gets the tincture from.”

“Why?”

“Because I think it’s the cause of my visits to variant histories.”

Burton and Swinburne emerged from the jungle-swathed Cauldron and strode westward along Leadenhall Street toward Cheapside. Fidget jogged along beside them, panting, his tongue flapping and his nose twitching as he detected a myriad of enthralling odours.

Swinburne asked, “Why do you think Saltzmann’s the source of your hallucinations?”

“I’ve told you, Algy, they’re not hallucinations. Initially, I thought the first incident was caused by my run-in with Spring Heeled Jack, but I took the tincture right afterward, and the next time I drank it, the second incident occurred. On that occasion, Jack wasn’t involved.”

At the Bank of England they flagged down a landau.

“Oxford Street,” Burton directed.

They boarded, and the carriage got moving.

In contrast to their journey to the Cauldron, their ride away from it was conducted in silence. Burton was pondering the disparate mysteries, while Swinburne was fuming about his friend’s dangerous addiction.

By the time they disembarked, it was snowing again, albeit lightly.

Swinburne jammed his floppy hat onto his springy hair, wound his long scarf around his neck, and dodged away from Fidget’s eager teeth.

“That’s the place,” Burton said, pointing a little way ahead.

Despite the weather, the famous thoroughfare was crowded, and they had to push through the milling pedestrians, hawkers and ne’er-do-wells to reach the pharmacy. They entered. A bell clanked over the door. In response to it, an individual emerged from a back room and stood behind the counter. He was a lanky, grey haired, gaunt-faced and terribly stooped old man, wrapped in a thick coat and with fingerless woollen gloves on his hands.

“Good afternoon, Sir Richard,” he said in a voice that sounded like creaking wood.

“Hello, Mr. Shudders,” Burton said. “How’s business?”

“Mustn’t grumble. Mustn’t grumble. Can I be of service? Saltzmann’s, is it? My stock is low, but I think I have two or three bottles remaining.”

“No,” Burton replied, “I have sufficient, but could you tell me where it comes from?”

“The supplier? Locks Limited, sir.”

“And where is that located?”

Shudders pushed out his lips, tugged at his right ear, and squinted his eyes. “I don’t rightly know. I started selling the tincture some five years ago after being approached by a company representative. Other than that youth—”

“Youth?” Burton interrupted.

“Why, yes, a very young man. He convinced me of the efficaciousness of the potion and left with me a case of bottles, promising to deliver more if I sold them.”

“Which you did?”

“The very next day. As a matter of fact, it was you who purchased them, and where they are concerned, you’ve been my principal customer.”

“Have I indeed?” Burton tried to remember how he’d become acquainted with Saltzmann’s. His normally excellent memory failed him. That, in itself, filled him with suspicion.

“By what method are the bottles delivered?” he asked.

“Whenever my stock is low, a wagon brings a new box and I pay for it on the spot.”

Swinburne interjected, “But how do you inform them when you’re running out?”

“I never have to. They always turn up at just the right time.”

“And you only have two or three bottles left,” Burton noted. “Which means you’re expecting another delivery soon?”

“Yes. Later today or tomorrow, I should think.”

The king’s agent pondered this for a moment. “Do they stop in the street?”

“No. There’s a delivery yard out back.”

“Mr. Shudders, for reasons I cannot go into, I have to investigate Locks Limited. Can I count on your cooperation?”

The pharmacist looked worried and wrung his hands. “Has there been some problem with the tincture, sir? Should I stop selling it?”

“No problem other than the mystery of its ingredients. Concerns have been raised that it might be extremely addictive.”

“So is laudanum, but there’s no law against selling that. I don’t think I’m in the wrong.”

“Nor am I accusing you. I’m intrigued, that is all.”

“Ah, well then. What can I do?”

“Do you happen to stock extract of anise?”

“Certainly.”

“I’d like to purchase a bottle. Will you then show us the back yard?”

The decoction was handed over, and a minute later, after Burton had secured Fidget’s lead to a chair in the shop, Shudders ushered the two men out of the back door and into a small cobbled area that opened onto an alleyway leading into Poland Street. It had been swept clean of snow, though a very thin layer had formed upon it since. Red flowers crowded around its edges.

“The wagon comes right into the yard?” Burton asked.

He received an affirmation.

“Are you expecting any other deliveries beside the one from Locks?”

Shudders shook his head. “Not until next Tuesday.”

Burton gave a grunt of satisfaction. He stepped across the yard, uncorked the bottle, and started to spill the gooey liquid onto the ground, dribbling it in a wide arc just inside the gate.

Shudders, blowing on his fingertips to warm them, looked on curiously.

When the bottle was empty, Burton returned to the pharmacist. “The moment the delivery is made, will you get word to me? You know my address.”

“Very well, Sir Richard. But what—?”

“I have my methods,” Burton responded.

Shudders swallowed nervously and looked perplexed.

Swinburne grinned.

They bid the pharmacist farewell and left the shop.

Burton turned up his collar and looked at the darkening sky. “These short winter days make me long for Africa, Algy. Do you think this horrible climate is responsible for the British imperative for expansion? Is our empire built upon drizzle and chill?”

“It’s a credible proposition,” the poet replied. “At least, when held against that which suggests a tonic could send a man to witness a specific event in other histories. Great heavens, Richard! Saltzmann’s is a sauce, not a sorcerer!”

“Where that mystery is concerned, I hope we’ve just placed a key in the Lock.”

“Ouch! Balderdash for mains and the worst kind of quippery for afters!” Swinburne complained.

“On which note, I intend to work up an appetite by walking home, where I shall await word from Krishnamurthy and Bhatti. Let us see whether old Babbage has cast any light on our various mysteries.”

“If you ask me, he’s just as likely to conjure up new confusions as he is to provide answers. The man is as mad as a March hare and becoming madder by the moment.” Swinburne jerked the end of his scarf from between Fidget’s teeth and wrapped an extra loop around his neck. “I shall call upon you tomorrow morning.” He took his leave and was quickly lost from view among the milling pedestrians, though Burton could hear him screeching for a cab.

The king’s agent set off toward the end of Baker Street. The freshly lit street lamps were each forming a nimbus in the falling snow, and the hunched metal backs of street-crabs glimmered in the illumination as they clanked along the busy thoroughfare. The gutters, filled with a mulch of trodden and crushed snow and flowers, looked to be running with blood, which, together with the rapidly blackening sky and the uncannily rubicund quality of the light, gave everything a thoroughly infernal appearance.