ABSTRACT
T HE popular conception of Arabia as a hot land is justified by the facts that the peninsula is nearly bisected by the tropic of Cancer and that the general average temperature is about 80° F., ranging from about 70° in the north to well over 80° in the south. But the altitude of the entire western half greatly lowers its temperature, so that here the winter weather can on occasion be quite cold, with sharp night frosts and even heavy snowfall. Indeed no greater c1irnatic contrast within a limited area can be imagined than that between the healthy, dry, bracing highlands with their sudden changeg of temperature and the monotonous, damp, enervating heat of the shores of the Red Sea and the Persian Gulf, where during the hot season the mean day and night air temperature iA near blood-heat, and the wet-bulb temperature up in the eighties or even nineties. Every part of Arabia at low or moderate altitudes iA liable to experience maximum day temperatures of over 100" during a large part of the year, and extensive areas over IIO
The lower deserts of the Rub' al Khali and the shoreA of the Persian Gulf record over 120°, whilst the surface of the deAert sand can, even in winter, be heated up to much higher temperatures under the powerful Arabian sun.
