Dyson leant back in his armchair and relit his pipe, and puffed thoughtfully. Phillipps began to walk up and down the room, musing over the story of violent death fleeting in chase along the pavement, the knife shining in the lamplight, the fury of the pursuer, and the terror of the pursued.
"Well," he said at last, "and what was it, after all, that you rescued from the gutter?"
Dyson jumped up, evidently quite startled. "I really haven't a notion. I didn't think of looking. But we shall see."
He fumbled in his waistcoat pocket and drew out a small and shining object, and laid it on the table. It glowed there beneath the lamp with the radiant glory of rare old gold; and the image and the letters stood out in high relief, clear and sharp, as if it had but left the mint a month before. The two men bent over it, and Phillipps took it up and examined it closely.
"Imp. Tiberius Cæsar Augustus," he read the legend, and then, looking at the reverse of the coin, he stared in amazement, and at last turned to Dyson with a look of exultation.
"Do you know what you have found?" he said.
"Apparently a gold coin of some antiquity," said Dyson, coolly.
"Quite so, a gold Tiberius. No, that is wrong. You have found the gold Tiberius. Look at the reverse."
Dyson looked and saw the coin was stamped with the figure of a faun standing amidst reeds and flowing water. The features, minute as they were, stood out in delicate outline; it was a face lovely and yet terrible, and Dyson thought of the well-known passage of the lad's playmate, gradually growing with his growth and increasing with his stature, till the air was filled with the rank fume of the goat.
"Yes," he said, "it is a curious coin. Do you know it?"
"I know about it. It is one of the comparatively few historical objects in existence; it is all storied like those jewels we have read of. A whole cycle of legend has gathered round the thing; the tale goes that it formed part of an issue struck by Tiberius to commemorate an infamous excess. You see the legend on the reverse: 'Victoria.' It is said that by an extraordinary accident the whole issue was thrown into the melting pot, and that only this one coin escaped. It glints through history and legend, appearing and disappearing, with intervals of a hundred years in time and continents in place. It was discovered by an Italian humanist, and lost and rediscovered. It has not been heard of since 1727, when Sir Joshua Byrde, a Turkey merchant, brought it home from Aleppo, and vanished with it a month after he had shown it to the virtuosi, no man knew or knows where. And here it is!"
"Put it into your pocket, Dyson," he said, after a pause. "I would not let any one have a glimpse of the thing, if I were you. I would not talk about it. Did either of the men you saw see you?"
"Well, I think not. I don't think the first man, the man who was vomited out of the dark passage, saw anything at all; and I am sure that the second could not have seen me."
"And you didn't really see them. You couldn't recognize either the one or the other if you met him in the street to-morrow?"
"No, I don't think I could. The street, as I said, was dimly lighted, and they ran like mad-men."
The two men sat silent for some time, each weaving his own fancies of the story; but lust of the marvellous was slowly overpowering Dyson's more sober thoughts.
"It is all more strange than I fancied," he said at last. "It was queer enough what I saw; a man is sauntering along a quiet, sober, every-day London street, a street of gray houses and blank walls, and there, for a moment, a veil seems drawn aside, and the very fume of the pit steams up through the flagstones, the ground glows, red hot, beneath his feet, and he seems to hear the hiss of the infernal caldron. A man flying in mad terror for his life, and furious hate pressing hot on his steps with knife drawn ready; here indeed is horror. But what is all that to what you have told me? I tell you, Phillipps, I see the plot thicken, our steps will henceforth be dogged with mystery, and the most ordinary incidents will teem with significance. You may stand out against it, and shut your eyes, but they will be forced open; mark my words, you will have to yield to the inevitable. A clue, tangled if you like, has been placed by chance in our hands; it will be our business to follow it up. As for the guilty person or persons in this strange case, they will be unable to escape us, our nets will be spread far and wide over this great city, and suddenly, in the streets and places of public resort, we shall in some way or other be made aware that we are in touch with the unknown criminal. Indeed, I almost fancy I see him slowly approaching this quiet square of yours; he is loitering at street corners, wandering, apparently without aim, down far-reaching thoroughfares, but all the while coming nearer and nearer, drawn by an irresistible magnetism, as ships were drawn to the Loadstone Rock in the Eastern tale."
"I certainly think," replied Phillipps, "that, if you pull out that coin and flourish it under people's noses as you are doing at the present moment, you will very probably find yourself in touch with the criminal, or a criminal. You will undoubtedly be robbed with violence. Otherwise, I see no reason why either of us should be troubled. No one saw you secure the coin, and no one knows you have it. I, for my part, shall sleep peacefully, and go about my business with a sense of security and a firm dependence on the natural order of things. The events of the evening, the adventure in the street, have been odd, I grant you, but I resolutely decline to have any more to do with the matter, and, if necessary, I shall consult the police. I will not be enslaved by a gold Tiberius, even though it swims into my ken in a manner which is somewhat melodramatic."
"And I for my part," said