INTRODUCTION. 



15 



AQRICULTlTvAL CArACIXrES. 



We have attempted to give a sketcli of the external features and spontaneous vegetation of 

 the region of country along the United States and Mexican boundary line. It now remains to 

 notice its adaptation to agriculture, and our remarks regarding this may all be embraced in one 

 general conclusion. 



Wherever the supply of water is constant, and sufficient for the purposes of irrigation, or 

 wherever the regular overflow of the rivers can be relied upon to supply the amount of moisture 

 req^uired for the growth of crops^ independently of the rains, in those places, and in those only, 

 can agriculture be pursued with success. 



The portions of the country best suited to cultivation are those wliich are capable of irrigation. 

 For these the supply of water is obtained, not only from the larger rivers, as the Rio Grande 

 and Gila, in which the head of water is increased by the construction of dams, but springs and 

 small water courses, these often lying in mountainous situations, are laid under tribute. 



In the course of the preceding sketch we have noticed the fact that the lower portions of the 

 numerous valleys are of a sterile and unproductive character, for the reason that the water of 

 the streams is absorbed before it reaches the portions which lie farther below, where, instead of 

 a running stream, we only find a sandy bed, with the adjoining region unfit for the purposes of 

 cultivation. 



Those places which are supplied with the necessary moisture by the overflow of the rivers 

 have a still more precarious dependence than those where irrigation is practiced. In these the 

 quantity of water cannot be regulated, and they are exposed to the two extremes of scarcity or 

 superabundance. One of the best examples of this system of cultivation is seen at Presidio 

 del Norte, where the Concho unites with the Eio Grande. As these two rivers have different 

 periods of high water the inhabitants are enabled to frequently secure two crops from the same 

 fields in one season. In order to accomplish this the first crop, depending upon the overflow of 

 the Eio Grande, must be sown and harvested in time to admit of the planting of the second 

 crop, depending upon the later rise of the Concho. All this depends upon so many contingent 

 circumstances that it is oftener attended by disappointment than by success^ and, between the 

 extremes of flood and drought, the people frequently suffer for want of food. 



We have already noticed that a large extent of country, though destitute of streams to supply 

 the water required in cultivation, receives from the atmosphere and clouds, in the form of dew 

 and rain, suflSicient moisture to permit the growth of the richest pasturage, and we have large 

 districts of unequalled grazing lands, so broad and so abounding in herbage as to compensate 

 for their deficiencies in other respects. Here the buifalo and antelope have already given place 

 to wild cattle and horses, and we look for the time when these shall yield in their turn to 

 domesticated flocks and herds, denoting that nomadic barbarism has been supplanted by 

 civilization, with its ameliorating influences. 



Many large tracts of this country must ever remain as deserts, being alike destitute of 

 vegetable and mineral resources ; but even these otherwise valueless regions are the very portions 

 which present the fewest impediments to travelling, and, indeed, form natural highways to 

 otherwise inaccessible parts of the country. 



Other facts connected with this part of the subject, as regards character of climate and general 



