The dunes were narrow. By half-past seven we were on a staring plain of glassy sand mixed with shingle, overspread by tall scrub and thorn bushes, with some good acacia trees. We rode very fast across this, myself in some discomfort; for I was not a skilled rider: the movement exhausted me, while sweat ran down my forehead and dripped smartingly into my gritty, sun-cracked eyelids. Sweat was actually welcome when a drop fell from the end of a tuft of hair, to strike on the cheek cold and sudden and unexpected like a splash; but these refreshments were too few to pay for the pain of heat. We pressed on, while the sand yielded to pure shingle, and that again hardened into the bed of a great valley, running down by shallow, interwoven mouths towards the sea.