CONCLUSION. 29 



this region, rendered it unnecessary to do more than make what may he strictly called a railroad 

 exploration. 



The examination of the eastern portion hy Capt. Pope, assisted &quot;by Lieut. Garrard, of the 

 dragoons, was made under the most disadvantageous circumstances, the party having heen 

 organized at a remote point, where neither instruments, nor assistants specially instructed in 

 the scientific branches connected with the survey, could be procured. It was, however, 

 creditably performed, and satisfactorily exhibits the topography and general character of the 

 country along the line surveyed. 



CONCLUSION. 



To aid in a comparison of the several routes, reference is made to a table prepared by Capt. 

 A. A. Humphreys, and hereto appended. 



With regard to the estimates of cost, although believed to be as accurate as can be made 

 tinder present circumstances, they are to be considered as intended not so much to show the 

 absolute sums of money which would build the several roads, as to represent the relative 

 quantities of materials and labor required for the purpose. If now tested in the actual con 

 struction of any one of the roads, they will doubtless be found to contain many errors; but as 

 the same data have been assumed on all the routes, the same amount of error will probably 

 be found in each, and the actual expense will thus preserve the same proportion. 



With regard to the equated lengths of the several roads, or, in other words, the influence 

 of ascents and descents upon the expense of working, it is proper to direct attention to the 

 remarks of the engineer, appended to the tables, in which he states that, on all the routes, the 

 amount reported will be subject to increase when the minor undulations of the ground shall be 

 measured ; and this increase will be greatest on those routes and in those portions where the 

 features of the country are less regular that is, where there are most of such minor undula 

 tions to be measured. The equated distances also affect the cost of working a road only 

 under certain circumstances, which may or may not exist on the contemplated route. 



A comparison of the results stated above, and of those exhibited in the tables referred to, 

 conclusively shows that the route of the 32d parallel is, of those surveyed, &quot;the most prac 

 ticable and economical route for a railroad from the Mississippi river to the Pacific ocean.&quot; 



This is the shortest route ; and not only is its estimated cost less by a third than that of 

 any other of the lines, but the character of the work required is such that it could be executed 

 in a vastly shorter period. It is obvious that a road on any of these routes, with the exception 

 perhaps of the 47th parallel, must be built continuously from the two extremities, and an 

 obstacle that arrests its progress at any point defers the commencement of all the work in 

 advance. The tunnels and much of the other work on the more northerly routes in the most 

 desolate regions are such as could not be commenced until a road was constructed up to those 

 points, and would then require a long period for their completion. 



On the southernmost route, on the contrary, the progress of the work will be regulated 

 chiefly by the speed with which cross-ties and rails can be delivered and laid, the nature of the 

 country being such that throughout the whole line the road-bed can easily be prepared in 

 advance of the superstructure. The few difficult points, such as the Pass of the Guadaltipe 

 and Hueco mountains, and the passes between the Rio Grande and Gila, would delay the work 

 but an inconsiderable period. 



This peculiarity of the ground presents another advantage in the fact that temporary tracks 

 could be laid upon the natural surface of the earth to almost any extent, to serve for the trans 

 portation ot materials and supplies. 



The climate on this route is such as to cause less interruption to the work than on any 

 other route. 



Not only is this the shortest and least costly route to the Pacific, but it is the shortest 

 and cheapest route to San Francisco, the greatest commercial city on our western coast; while 

 the aggregate length of railroad lines connecting it at its eastern terminus with the Atlantic 



