DEPARTMENT OF BOTANICAL RESEARCH. 55 



The slopes toward the Nile are much longer and the underflow runs more 

 deeply amid the coarse material in the "khors," while the desert grasses and 

 spinose types are the most prominent constituents of the vegetation. The 

 entire region is one which offers about the same problems in colonization as 

 portions of Mexico and southwestern United States. 



Work in the Libyan Desert was carried out chiefly by means of a camel 

 caravan. The party proceeded by rail to the Merkez of the Western Egypt 

 Development Company, in the oasis of Kharga, about 120 miles west of the 

 Nile, early in February. A dozen camels had been selected for transport 

 and riding animals were secured, and Abu Salem, a well-known sheik, acted 

 as caravan leader. The route carried the party to the oasis of Dakhla, 

 thence northward to the oasis of Farafra, thence northeastward to the oasis 

 of Baharia, and back to the Nile at Samalayut and Minia, where the caravan 

 was discharged. The total distance traversed by the caravan was about 500 

 miles, which was done at the average rate of 25 miles per day. 



The Libyan Desert offers highly characteristic physical features, which 

 are duplicated in part only in other deserts, and are unexpectedly in contrast 

 with arid regions in the Sahara in southern Algeria examined by Dr. W. A. 

 Cannon and Prof. Hans Fitting. 



The water in the Libyan Desert is either plutonic or is derived from catch- 

 ment areas so widely distant that the supply is independent of local climatic 

 conditions outside of evaporation. The exclusively eolian erosion, with the 

 resultant rounded hills, "sogag," "karafesh," and great sand ribbons hun- 

 dreds of miles in length, gives a landscape widely different from those in 

 which precipitation plays a part. The vagrant rainstorms furnish an uncer- 

 tain supply of moisture which supports some vegetation in the dune areas 

 and among creviced rocks. Distances as great as 40 miles were traversed 

 without encountering a single plant, dead or alive. Lizards, beetles, rodents, 

 birds, and gazelles were seen in places widely separated from sources of 

 water, and must have depended upon the scanty proportion of moisture in 

 their food. The quantity of water consumed by men and animals seemed 

 to be less than that necessary in American deserts, while "sunburning" and 

 other physiological effects of light and heat were greater. The total evap- 

 oration at some places in the eastern part of this region and in the Red Sea 

 Province has been found to amount to over 200 inches yearly, or about 

 double the amount measured in an American locality, although observations 

 of this matter have not been made in the driest regions in either desert. 



Only climatic changes of great amplitude would leave enduring records 

 in the Libyan Desert. Remains of habitations and extended cultivation 

 would, in most cases, depend upon engineering enterprise and efficiency in 

 irrigation. The present size of the oases might be increased by a unified con- 

 trol of the water supply, and it seems highly probable that exploratory borings 

 might tap new supplies which would serve in the formation of new oases. 



The detailed results of the field studies are now being prepared for publi- 

 cation. 



