She shrugged her shoulders with a little laugh. "We fell out, Aubrey and I. He wanted to go to America. I wanted a trip into the desert. We quarrelled for two whole days and half one night, and then we compromised. I should have my desert tour, and Aubrey should go to New York; and to mark his brotherly appreciation of my gracious promise to follow him to the States without fail at the end of a month he has consented to grace my caravan for the first stage, and dismiss me on my way with his blessing. It annoyed him so enormously that he could not order me to go with him, this being the first time in our wanderings that our inclinations have not jumped in the same direction. I came of age a few months ago, and, in future, I can do as I please. Not that I have ever done anything else," she conceded, with another laugh, "because Aubrey's ways have been my ways until now." "But for the sake of one month! What difference could it make to him?" he asked in astonishment. "That's Aubrey," replied Miss Mayo drily. "It isn't safe," persisted Arbuthnot. She flicked the ash from her cigarette carelessly. "I don't agree with you. I don't know why everybody is making such a fuss about it. Plenty of other women have travelled in much wilder country than this desert." He looked at her curiously. She seemed to be totally unaware that it was her youth and her beauty that made all the danger of the expedition. He fell back on the easier excuse. "There seems to be unrest amongst some of the tribes. There have been a lot of rumours lately," he said seriously. She made a little movement of impatience. "Oh, that's what they always tell you when they want to put obstacles in your way. The authorities have already dangled that bogey in front of me. I asked for facts and they only gave me generalities. I asked definitely if they had any power to stop me. They said they had not, but strongly advised me not to make the attempt. I said I should go, unless the French Government arrested me.... Why not? I am not afraid. I don't admit that there is anything to be afraid of. I don't believe a word about the tribes being restless. Arabs are always moving about, aren't they? I have an excellent caravan leader, whom even the authorities vouch for, and I shall be armed. I am perfectly able to take care of myself. I can shoot straight and I am used to camping. Besides, I have given my word to Aubrey to be in Oran in a month, and I can't get very far away in that time."