“Well, I didn’t spend much time in Trob. I was just passing through, you know—”

“Oh, it’s not in Trob. I speak Trob because there are many beTrobi sailors in our ports. Des Palargic is the major seaport of the Agatean Empire.”

“Never heard of it, I’m afraid.”

Twoflower raised his eyebrows. “No? It is quite big. You sail turnwise from the Brown Islands for about a week and there it is. Are you all right?” He hurried around the table and patted the wizard on the back. Rincewind choked on his beer-The Counterweight Continent!

Three streets away an old man dropped a coin into a saucer of acid and swirled it gently. Broadman waited impatiently, ill at ease in a room made noisome by vats and bubbling beakers and lined with shelves containing shadowy shapes suggestive of skulls and stuffed impossibilities.

“Well?” he demanded.

“One cannot hurry these things,” said the old alchemist peevishly. “Assaying takes time. Ah.” He prodded the saucer, where the coin now lay in a swirl of green colour. He made some calculations on a scrap of parchment.

“Exceptionally interesting,” he said at last.

“Is it genuine?”

The old man pursed his lips. “it depends on how you define the term,” he said. “if you mean: is this coin the same as, say, a fifty-dollar piece, then the answer is no.”

“I knew” it,” screamed the innkeeper, and started towards the door.

“I’m not sure that I’m making myself clear,” said the alchemist. Broadman turned round angrily.

“What do you mean?”

“Well, you see, what with one thing and another our coinage has been somewhat watered, over the years. The gold content of the average coin is barely four parts in twelve, the balance being made up of silver, copper—”

“What of it?”

“I said this coin isn’t like ours. It is pure gold.”

After Broadman had left, at a run, the alchemist spent some time staring at the ceiling. Then he drew out a very small piece of thin parchment, rummaged for a pen amongst the debris on his workbench, and wrote a very short, small, message. Then he went over to his cages of white doves, black cockerels and other laboratory animals. From one cage he removed a glossy coated rat, rolled the parchment into the phial attached to a hind leg, and let the animal go.