30 CONCLUSION. 
and Gulf seaports is less than the aggregate connexion with any other route, as will be seen 
by reference to the appended table B. 
With regard to the circumstances which affect the cost of working and maintaining the 
road, they are more favorable than on any other route. In this dry climate the decay of 
cross-ties and other timber would be very slow, and the absence of severe frost would have 
a most important influence upon the permanence of the road-bed, and heavier grades could be 
adopted than in a climate where ice and snow prevail. 
The snows on all the other routes, except that of the 35th parallel, could not fail at 
certain seasons to suspend the working of the road, for on all, such snows are known to have 
fallen as would interpose an effectual barrier to the passage of trains. Such an occurrence in 
this desolate region would be attended with more serious consequences than in inhabited districts. 
In only one important respect is this route supposed to be less favorable than some of the 
others, and that is, in the supply of fuel. The difference, however, in favor of the others is 
not great, unless the existence of coal at certain points along those routes where it is indicated 
should be verified by further examination. The cost of fuel is about one-fifth of the whole 
expense of maintaining and working a railroad. 
The grades of the several routes, and other similar information, will be found upon the sheets 
of profiles compiled in the office. 
In the determination of the explorations proper to be made—in the examination of the reports 
of the suveying parties, the preparation of the profiles, and of a general map to exhibit, in 
their geographical relation to each, all the routes of which an instrumental examination had 
been made—I am greatly indebted to the assistance which has been rendered by the officers of 
the corps of topographical engineers employed in the office established here in connexion 
with the explorations directed by the act; and I will here especially acknowledge my obliga- 
tions to Major W. H. Emory, whose extensive knowledge of the western regions of our country, 
no small part of which he had actually explored, and whose sound judgment in all things con- 
nected with topographical reconnaissances and field operations, gave me important aid in the or- 
ganization of the work and the subsequent office examinations necessary to systematize its results. 
When, in August, 1854, Major Emory’s duties as commissioner to run the boundary- 
line between Mexico and the United States separated him from further connexion with these 
explorations, he was succeeded by Capt. A. A. Humphreys, whose high scientific attainments 
and power of exact analysis had been manifested in several important positions which he 
had held, and are further shown in the able and comprehensive examination, herewith sub- 
mitted, of the reports of the several parties of exploration. 
Lieut. G. K. Warren, first under Major Emory, and subsequently under Captain Humphreys, 
has been specially intrusted with the preparation of the material and the construction of the 
general map, together with the compilation of profiles of all the routes which had been instru- 
mentally surveyed, and the collection of all general information which would aid in the 
determination of the question before the department. In these duties he has recently had the 
zealous and efficient aid of Lieut. H. L. Abbott. 
These laborious and important duties have been performed by the officers above named 
with the most commendable diligence and intelligence, and much of whatever success belongs 
to the preparation and presentation of the matter collected is due to these ofticers. 
Capt. McClellan, of the corps of enginers, after the completion of his field operations, was 
directed to visit various railroads, and to collect information of facts established in the con- 
struction and working of existing roads, to serve as data in determining the practicability of 
constructing and working roads over the several routes explored. The results of his inquiries 
will be found in a very valuable memoir herewith submitted. 
Very respectfully, your obedient servant, 
JEFEF’N DAVIS, Secretary of War. 
Hon. Linn Boyp, 
Speaker of the House of Representatives. 
