"Mr. Vaux?" came a distinct voice which he did not recognise.
"Yes," he snapped, "who is it?"
"Miss Erith."
"Oh—er—surely—surely! GOOD-evening, Miss Erith!"
"Good-evening, Mr. Vaux. Are you, by any happy chance, quite free this evening?"
"Well—I'm rather busy—unless it is important—hum—hum!—in line of duty, you know—"
"You may judge. I'm going to try to secure that code-book to-night."
"Oh! Have you called in the—"
"No!"
"Haven't you communicated with—"