114 
WATER — ROCKS. 
or other travellers passing through their country, 
and coming from Mourzuk. In the event of their 
committing a bad action, the Bey says he may be 
compelled to make reprisals; so it is quite clear 
the letter is written entirely on our account, and 
perhaps is a preliminary measure to making re- 
prisals. Nous verrons. This letter is only ad- 
dressed to the people of Aheer. 
If water be the sustaining and even the genera- 
tive force of vegetation in the desert, it is also the 
destruction of trees and herbage ; for along the line 
of the current of the wady are seen immense 
numbers of dead and overthrown trees, torn from 
their roots by the force of the water in the rainy 
season. En-Noor paid me a visit this afternoon, 
and took a nap in my tent. 
13^. — We rose early, but did not start till about 
nine o'clock. This was the coldest day we have yet 
experienced : the heavens were overcast with clouds. 
We came five hours ; our course irregular, but 
always south-east ; the track through wadys filled 
with the usual trees of the tholukh species. Yester- 
day were seen numbers of large butterflies, but 
to-day, on account of the cold, few. Flies innu- 
merable follow the caravan. The rocks were, as 
yesterday, many conic-formed, and others rounded 
or appearing in ranges, like huge haycocks : granite, 
sandstone, and trachite. We have in the distance 
before us, a peculiarly shaped rock of considerable 
height, called Mari, in the midst of a range. We are 
