Most important, however, are the temperamental differences in men which make some desirous of giving themselves to the cultivation of a small area of irrigated land under intensive conditions and others to dry-farming under extensive conditions.  In fact, it is being observed in the arid region that men, because of their temperamental differences, are gradually separating into the two classes of irrigation-farmers and dry-farmers.  The dry-farms of necessity cover much larger areas than the irrigated farms.  The land is cheaper and the crops are smaller.  The methods to be applied are those of extensive farming.  The profits on the investment also appear to be somewhat larger.  The very necessity of pitting intellect against the fierceness of the drouth appears to have attracted many-men to the dry-farms.  Gradually the certainty of producing crops on dry-farms from season to season is becoming established, and the essential difference between the two kinds of farming in the arid districts will then he the difference between intensive and extensive methods of culture.  Men will be attracted to one or other of these systems of agriculture according to their personal inclinations.

The scarcity of water

For the development of a well-rounded commonwealth in an arid region it is, of course, indispensable that irrigation be practiced, for dry-farming of itself will find it difficult to build up populous cities and to supply the great variety of crops demanded by the modern family.  In fact, one of the great problems before those engaged in the development of dry-farming at present is the development of homesteads in the dry-farms.  A homestead is possible only where there is a sufficient amount of free water available for household and stock purposes.  In the portion of the dry-farm territory where the rainfall approximates twenty inches, this problem is not so very difficult, since ground water may be reached easily.  In the drier portions, however, where the rainfall is between ten and fifteen inches, the problem is much more important.  The conditions that bring the district under the dry-farm designation imply a scarcity of water.  On few dry-farms is water available for the needs of the household and the barns.  In the Rocky Mountain states numerous dry-farms have been developed from seven to fifteen miles from the nearest source of water, and the main expense of developing these farms has been the hauling of water to the farms to supply the needs of the men and beasts at work on them.  Naturally, it is impossible to establish homesteads on the dry-farms unless at least a small supply of water is available; and dry-farming will never he what it might be unless happy homes can be established upon the farms in the arid regions that grow crops without irrigation.  To make a dry-farm homestead possible enough water must be available, first of all, to supply the culinary needs of the household.  This of itself is not large and, as