116 ROUTE TO THE GULF. 



attainment, with the locomotive, of twenty feet in altitude, is equivalent 

 to the transit of a mile upon a horizontal plane, we would have (other 

 conditions heing equal) a difference of one hundred miles in horizontal 

 distance in favor of the route under consideration, over one which should 

 pass the mountains at an elevation of seven thousand feet. 



The difference of elevation of the Rio Del Norte in the vicinity of 

 Dona Ana, and the crest of the mountains in latitude 32° being about 

 one thousand feet, and the distance between the two positions about one 

 hundred miles, gives an average grade (which is said to be very uni- 

 form) of ten feet per mile in ascending the eastern slope of the mount- 

 ains. From the summit to the mouth of the Gila, a distance of three 

 hundred and eighty miles, the difference in altitude, barometrically de- 

 termined, is four thousand seven hundred and forty-six feet, which (sup- 

 posing the slope to be uniform) admits of a gradient of about twelve 

 and a half feet to the mile in descending the Pacific side of the 

 mountains. 



The road upon this side would be much more circuitous in its course 

 than upon the other ; the grades will be increased upon the undulatory 

 portions of the country, and some difficulty may be anticipated in passing 

 the great canon of the Gila, provided the road is confined exclusively to 

 the limits of our own territory ; but a gentleman of scientific attainments, 

 who has examined this route carefully, is of the opinion that no greater 

 impediments will be met with upon the Gila than are found upon the 

 Hudson river road. From the Colorado to the Pacific (unless some other 

 pass is discovered) the road must penetrate the " Sierra Nevada" chain, 

 through what is called "Warner's Pass." 



The summit of this defile is situated north of the general course of 

 the road, and the approaches to it, upon both sides, are somewhat tor- 

 tuous. It is about one hundred miles distant from the confluence of the 

 Gila with the Colorado, and about eighty miles from San Diego on the 

 Pacific. 



The elevation of the Pass above tide-water being three thousand and 

 thirteen feet, and that of the Colorado, at the mouth of the Gila, two 

 hundred and fifty-four feet, we would have an average gradation of 

 twenty-seven and a half feet per mile in the ascent of the eastern slope, 

 and a descent from the Pass of thirty-seven and a half feet to the mile 

 in reaching San Diego. 



Should it be found desirable, on arriving at the mouth of the Gila, to 

 turn the course of the road, and run it down the valley of the Colorado 

 to the head of the Gulf of California, I am informed by persons who 

 have examined this section that the surface is free from obstructions, 



