THE EARLY MORNING COLD. 397 



been heated to perhaps 130 or 140 Fahr. during 

 the day, retains its heat for a long 1 time, and even 

 when it cools upon the surface, feels quite warm two 

 or three inches below it when turned over. In rocky 

 districts also, the hot stones continue to give out a 

 sensible degree of heat for many hours after sunset : 

 indeed for a considerable time afterwards, the incau- 

 tious traveller sitting down upon a rock in thin clothes, 

 is often startled to find it most unpleasantly hot. 

 Nevertheless, though everything may be glowing like 

 a furnace at sundown; the atmosphere rapidly co9ls 

 down, and the nights are therefore generally cool and 

 pleasant, and towards morning especially, not unfre- 

 quently become bitterly cold. Sultry and oppressive 

 nights, when they occur, are usually experienced only 

 during the prevalence of the hot winds. 



The sudden diminution of temperature in dry regions, 

 by night, is, however, a matter which every prudent 

 traveller will do well to guard against by following 

 the fashionable custom, even in these wild solitudes, 

 of " dressing for the evening " in garments suitable 

 to the occasion. The frame debilitated by the exhausting 

 heat of day is keenly sensitive to chill and he will 

 be apt to find the protection of thick warm things, 

 and even an ulster, none too much for him; some 

 travellers have even gone so far as to recommend 

 furs. Mr. Falkonberg, one of the engineers employed 

 upon the survey of the proposed Soudan Railway, for 

 instance, bitterly complains of the bad advice with which 

 he was favoured by inexperienced friends, when making 

 up his kit for the Egyptian Soudan, and says: 



" Our great surprise was to find the nights in December 

 and January as cold as 45 F., on a rough average, never 



