The Introduction of Commercial Crops.—The problem can only be satisfactorily approached by way of a preliminary and exhaustive examination of the conditions actually obtaining ; followed by a study of research in other regions directed to a determination of the circumstances of climate and soil best suited to the growth of specific crops. An attempt may then be made to secure comparable conditions locally. The degree of control over the various factors involved, which may be assured by ordinary and commercial measures, is strictly limited, and the results can only approximate to a previously determined optimum. From this circumstance will arise the need for further inquiry as to the separate and combined effects of temperature, moisture and sunshine, both in their normal and abnormal proportions, upon the annual yields of staple crops. With this must be coupled a determination of the tolerance or adaptability of exotic plants to the altered conditions which will furnish a measure of their acclimatisation.

A Problem of Acclimatisation.—Three methods are available in the latter connection. The statistical system is an early-established means of ascertaining the effect of climate, by comparing the statistics of the successive annual harvests in the country at large with the annual metebrologi'cal returns. It lacks definition and scientific accuracy and has a very limited value. A second method is based upon the experimental cultivation of plants in rooms or other structures where temperature, moisture and other conditions are under control. Successive slight changes in each of the factors of the artificial climate will furnish data for the establishment of laws of acclimatisation. A less perfect application of this system is found in comparative field experiments where a serial modification of one factor is applied with a maintenance of uniformity, as far as possible, in other conditions. A final method lies in the detailed study of the individual plant accompanied by delicate measurements and microscopic examination of the processes of growth, nutrition and transpiration, as affected by sunshine, temperature and- moisture. The following report reflects a preliminary inquiry into the nature of the desert environment, modifications esfiected therein by irrigation, drainage, cultivation and manuring, and the character of crop growth in the amended conditions as revealed by comparative plot work, experimental cultivation of individual plants and a physiological examination of growth processes. To ensure reliability the field and laboratory experiments have been conducted independently and the records only subsequently associated. By such means mutual control and a reduction in the margin of experimental error are assured.

The Desert Soils.—The outstanding features of all desert areas are, firstly, the aridity of the soil. Loam is here as dry as sand or stony soil, for all kinds of soil are alike inadequately supplied with moisture. The soil varies greatly