211 



by a reference to tlie table. In some parts of the desert 

 the temperature from day to day is very equable, and 

 the divn-nal range not very great, but in this respect the 

 desert localities greatly differ, Ehind states that his ob- 

 servations corroborate, with regard to dryness, those of 

 Dr. Barclay, who found, " taking zero to represent 

 summer-drought in England, his hygrometer shew a 

 mean of 7'5 degrees of dryness when sailing between 

 Thebes and Assouan, from the 17th to the 23rd of January, 

 while the mean was 12*2 in a tomb at Geezeh, for a cor- 

 responding number of days, from the 13th to the 19th of 

 March, the temperature at both periods being very nearly 

 identical, and the same bright, cloudless weather pre- 

 vailing." 



Rain is nearly unknown in Nubia, and is also very rare 

 in Upper Egypt. During nearly three months spent on 

 the Nile in 1857 Ave had only three showery days, and on 

 two of these the showers Avere only very slight and 

 short. 



A friend, just returned from Egypt, and who has fur- 

 nished me Avith some very valuable information regard- 

 ing the Aveather on the Nile during the last Avinter, 

 1857-58, informs me that during more than three months 

 they had only one shower (at Edfoo on the 5th February). 

 Even the aboA^e appears to be above tlie aA'^erage num- 

 ber of Avet days, if we are to credit the statements of 

 travellers. Pococke " had been told that there, in eight 

 years, it had been known to rain but tAvice very hard for 

 half an hour," Satisfactory evidence, hoAvever, exists, 

 both on the ]\Iokattam and Libyan liills, that very heavy 

 rains do occasionally fall throughout Upper Egypt, for 

 they exhibit numerous deep Avatei'-courses with well- 

 marked traces of the force and rapidity of the torrents. 

 On the 17th of January, near Girgeh, lat. 2G|-''N., there was 

 in the evening much lightning and some thunder, with 



