108 BOTANICAL FEATURES OF NORTH AMERICAN DESERTS. 
the climate, regardless of aridity. One of the most important develop- 
ments of modern agriculture is that of dry farming, in which forms of 
economic plants are sought which will produce crops under arid con- 
ditions, and constant and assiduous attention is being given to the devel- 
opment of cultural methods which will facilitate the growth of plants in 
deserts and conserve the soil moisture by checking evaporation. These 
and other individual adaptations of the human animal are of extreme 
interest, particularly when considered by the archeologist engaged in 
the study of the ancient civilization of desert peoples. (C. S. Scofield, 
Dry Farming in the Great Basin, Bulletin No. 103, Bureau of Plant 
Industry, U.S. Department of Agriculture, Washington, 1907.) 
One of the most difficult problems to solve is that of transportation 
in the desert, and there are extensive areas in American deserts that have 
not yet been systematically explored by reason of this condition. 
The camel is perhaps the most extensively used of any means of 
transportation, and as such he has played an important part in the his- 
tory of the human race in the arid regions of Asia and Africa. This 
animal has also come to be of great usefulness in Australia, where it was 
introduced in 1846, and a later importation of these animals, brought in 
1860, accompanied the Burke and Wills Expedition across the continent. 
In this same period efforts were made to make use of the camel in Amer- 
ican deserts, and although the conditions were undoubtedly and still 
seem quite as favorable, the movement was a failure by reason of pre- 
judice, and of the organization of transport of burros, horses, and mules 
already in a high state of specialization in this region. The extension of 
railways to tap mining regions and the usefulness of the modern motor 
car, as proved in the deserts of Nevada, now make any further considera- 
tion of the camel unnecessary along main lines of travel, while the solitary 
traveler or the small party following personal routes have available ani- 
mals and supplies, so that the most economical outfit is that of horses, 
mules, and burros. A camel is reputed to be able to carry a load of 600 
pounds with ease, but the same amount might be taken by three or four 
burros at a cost of original investment and maintenance only a fraction of 
that of the camel-train. It is to be said, however, that a small efficient 
camel-train would make possible the scientific exploration of the deserts 
of western Sonora and of the region traversed by the Camino del Diablo 
with some certainty of success. 
A comprehension of the part that water plays in existence and travel 
in the desert is to be gained only by experience. Some of the native 
animals, such as mice and other small rodents, have been known to live 
on hard seeds without green food for periods of several months, or even 
as long as two or three years, and nothing in their behavior indicated that 
they ever took liquid in any form. (F. V. Coville, Desert Plants as-a 
Source of Drinking Water, Smithsonian Reports for 1903, pp. 499-505. 
1904.) 
