When we ran out upon the floor of the narrow valley which separated the range of dunes we had just crossed from the next one, I tapped the driver on the shoulder. “Stop a moment,” I said. “What is the matter?” asked my wife, as I started to clamber down. “Are you going to take a picture?” “No,” I told her. “I am going to take my hat off to the car.” [Illustration: TO PROVE THAT WE WERE REALLY THERE Our camp in the Sahara. By day it was as hot as the stoke-hole of an oil-tanker in the Red Sea in midsummer, but with the setting of the sun the mercury frequently fell sixty degrees and we shivered beneath our heavy blankets] Thenceforward, for hundreds of miles, we zigzagged, now up, now down, through a bewilderment of dunes, a hopeless confusion of sand hills and ridges, valleys and hollows, which stretched away on one hand to meet the mountains of the Aurés and on the other to vanish in the vast spaces of the mid-Sahara. It was like motoring over an unending succession of very steeply pitched and lofty roofs, roaring up one side, pausing for an instant on the ridge-pole, and then hurtling down the other. Under the midday sun the dunes were as dazzling as snow, and a few chimneys here and there were all that was needed to make me feel like an up-to-the-minute Santa Claus. Though tremendously exhilarating, it was also extremely fatiguing, for the constant swaying and pitching of the car like a small boat in a heavy sea, the necessity of hanging on for dear life, put a severe strain on every bone and muscle in the body. When we camped that night I ached as I have ached but once before, at the end of my first long camel-ride in Arabia. Only once did we encounter serious trouble. We had charged an exceptionally steep dune, and, unable to arrest the momentum of the car when we gained the top, had hurtled down the reverse slope to find ourselves imprisoned in a deep pocket, or hollow, in the sands. The dunes rose so precipitously on every hand that there was no space in which to get a flying start. It looked to me as though we were going to have an opportunity to qualify as Shriners by a long, long march over the hot sands, for the nearest human habitation, so our Arab guide informed us, was a hundred kilometers away. But as soon as the chauffeur realized the hopelessness of trying to extricate the car by ordinary methods, he resorted to the windlass contrivance I have already described, which hauled us out of trouble as easily and almost as quickly as a steam-winch hoists cargo out of the hold of a steamer.