"Filthy things!" he said. "Why do you keep them?"
Ferrara shrugged his shoulders.
"Who knows?" he answered enigmatically. "They might prove useful, some day."
A bell rang; and from Ferrara's attitude it occurred to Cairn that he was expecting a visitor.
"I must be off," he said accordingly.
And indeed he was conscious of a craving for the cool and comparatively clean air of Piccadilly. He knew something of the great evil which dwelt within this man whom he was compelled, by singular circumstances, to tolerate. But the duty began to irk.
"If you must," was the reply. "Of course, your press work no doubt is very exacting."
The note of badinage was discernible again, but Cairn passed out into the mandarah without replying, where the fountain plashed coolly and the silver mibkharah sent up its pencils of vapour. The outer door was opened by the Oriental servant, and Ferrara stood and bowed to his departing visitor. He did not proffer his hand.
"Until our next meeting. Cairn, es-selâm aleykûm!" (peace be with you) he murmured, "as the Moslems say. But indeed I shall be with you in spirit, dear Cairn."
There was something in the tone wherein he spoke those last words that brought Cairn up short. He turned, but the doors closed silently. A faint breath of ambergris was borne to his nostrils.