160 
This tree was in full fructification as I passed. It is 
thorny, and on the fruit is a great quantity of resinous 
gluten, which might become useful to chymists. The 
pulp of the fruit, after the extraction of the oil, affords 
a fine food for oxen. This part was covered with a 
wood of these trees, of ten to twelve days journey, exten- 
ding from north to south, in which rhe inhabitants have 
no other trouble but to gather the fruit. W ould it not 
be possible to transplant this interesting tree into the 
southern parts of Europe? Such an acquisition would, 
in my opinion, be worth more than the addition of a 
province. 
Monday, 30th April. We renewed our journey at 
half past ten in the morning, in the direction of W. S. 
W. An hour after we came out of the wood, passed 
some moveable sandy hills, and a little after twelve we 
arrived at Suera or iMogador, which was the end of our 
expedition. 
The country presented no change from that which 
we passed yesterday. The sandy plain into which we 
had come may with truth be called a little Sahara; the 
wind is there of a surprising rapidity, and the sand so 
extremely fine, that it forms on the ground some waves, 
which look like those of the sea. These waves rise up so 
fast, that in a very few hours a hill of about 20 to- 30 feet 
high is transported from one place to another. I never 
thought it possible, and did not believe it till I was convin- 
cedofit by my own eyes. This transportation of these hills ? 
however, does not take place all of a sudden, as is 
generally believed, and it is by no means capable of sur- 
prizing and burying a caravan which is on the march s 
It is easy to describe the manner in which this transposi- 
