INSTRUCTIONS FROM THE WAR DEPARTMENT. 
War Department, October 2, 1854. 
Sir : The following duties are assigned to you, under the appropriation for continuing explo¬ 
rations and surveys, to ascertain the most practicable and economical route for a railroad from 
the Mississippi river to the Pacific ocean. 
1st. To make such explorations and surveys as will determine the practicability of a railroad 
from the Bay of San Francisco to the plains of Los Angeles by a route west of the Coast Range. 
2d. To determine whether the valley of the Mojave river joins that of the Colorado, and will 
afford a practicable route for a railroad ; and to explore the line recommended for examination 
by Lieut. Whipple, from Soda lake, Mojave river, to the Colorado river, by the Chem-e-hue- 
vas plain or valley. 
3d. To make the additional examinations and surveys, recommended in your report, upon 
the route from the Pimas villages to the Rio Grande. 
The geological examinations and surveys over this portion of the route are to be made with 
an especial view to obtaining an ample supply of water, for railroad purposes, by artesian wells, 
or by other means, if that prove to be improbable. 
It is unnecessary to enter into details as to the nature of the surveys required, and of the in¬ 
formation to be collected. They will be such as to furnish all the important elements in the 
solution of the question of practicability and economy in location, construction, working, and 
support of a railroad communication through the region of country passed over. 
The surveys in the mountain passes will be sufficiently careful and minute to determine with 
precision their practicability or impracticability. 
The geological information is considered to be especially valuable, not only as determining 
the character of the country, the nature of the difficulties to be overcome, and the quality, po¬ 
sition, and extent of the building materials to be found, but in ascertaining the probability 
of supplies of water in arid regions, at suitable distances for railroad purposes, and for irriga¬ 
tion, where this is essential to agriculture. In these arid regions the collection of soils becomes 
of additional interest. 
Your attention will be directed to the botany and natural history of the country, and to 
such other objects tending to illustrate its present and future condition and resources, to which 
the attention of the parties heretofore organized has been called, so far as they have a practical 
bearing upon the question of building and supporting a railroad. 
A ^comparison of profiles, over the same lines, made by the barometer and spirit level, on 
the surveys of Lieutenant Williamson, promises to yield some interesting information upon 
barometric levelling ; additional means of comparison are desirable. 
To execute these duties you are authorized to employ the following assistants, viz : A 
geologist, civil engineer, draughtsman, meteorologist and computer, at the rates proposed by you; 
they will receive, in addition to their compensation, the actual cost of transportation to and from 
