He took his departure as soon as the doctor had returned with the police, and drove back to his rooms. A search through the Encyclopædia told him nothing of Ain-Sefra; but, on the other hand, he could not look at the article on Algeria without the Foreign Legion leaping to his eyes at once--so great and magnificent a part it played in the modern history of that colony. The Foreign Legion! Warrisden jumped to the conviction that there was the secret of Tony Stretton's disappearance. Every reason he could imagine came to his aid. Let a man wish to disappear, as, from whatsoever reason, Tony Stretton did, where else could he so completely bury himself and yet live? Hardships? Dangers? Yes. But Tony Stretton had braved hardships and dangers in the North Sea, and had made light of them. A detachment of the Foreign Legion might well be stationed at this oasis of Ain-Sefra, of which his Encyclopædia knew nothing. He had no doubt there was a trooper there, serving under some false name, who would start if the name of "Stretton" were suddenly shouted to him behind his back.

Warrisden wrote no word of his conjecture to Pamela; he wished to raise no hopes which he could not fulfil. Convinced as he was, he wished for certain proof. But in fulfilment of his promise he wrote to Pamela that night. Just a few lines--nothing more, as she had asked. But in those few lines he wrote that he would like her to procure for him a scrap of Tony Stretton's handwriting. Could she do it? In a week the scrap of handwriting arrived. Warrisden, looking at it, knew that the same hand had addressed the envelope at Ain-Sefra to Mr. Chase.

Warrisden was ready now, if the summons to service should come once more from Pamela.

CHAPTER XXI

[CALLON REDIVIVUS]

All through that autumn Pamela watched for Tony's return, and watched in vain. Winter came, and with the winter a letter from Mr. Mudge. Lionel Callon had booked his passage home on a steamer which sailed on Christmas Eve from the port of Valparaiso. Pamela received the news one morning of December. She hunted that day with the Quorn, and for once her thoughts were set on other matters than this immediate business. The long grass meadows slipped away under her horse's feet the while she pondered how once more the danger of Callon's presence was to be averted. At times she hoped it would not need averting. Callon had been eighteen months away, and Millie was quick to forget. But she was no less quick to respond to a show of affection. Let Callon lay siege again persistently, and the danger at once was close. Besides, there were the letters. That he should have continued to write during the months of his absence was a sign that he had not forgone his plan of conquest.

Pamela returned home with a scheme floating in her mind. Some words which her mother had spoken at the breakfast-table had recurred to her, and at tea Pamela revived the subject.

"Did you say that you would not go to Roquebrune this winter, mother?" she asked.

"Yes," Mrs. Mardale replied; "I have been for so many winters now. I shall stay in England, for a change. We can let the Villa Pontignard, no doubt."

"Oh, there is no hurry," said Pamela. She added, "I shall be going to London to-morrow, but I shall be back in the evening."