6 LETTER TO OFFICER IN CHARGE OF EXPLORATIONS, ETC. 
limits of a strictly official communication: but a record of the every-day incidents of travel, 
set down while fresh in the mind, serves to convey a general idea of a country that can scarcely 
be imparted in any other way, and can hardly fail of reproducing, to some extent, in the mind 
of the reader the impression made upon that of the traveller. 
In passing from the Colorado eastward, an opportunity was afforded of forming a connexion 
between the Big Sandy, on Lieutenant Whipple’s railroad route, and the point upon the river 
north of the Needles. The examination verified the judgment of Lieutenant Whipple, who, 
though prevented from actually passing over the country, had selected it for a railroad location. 
The distance by Whipple’s travelled route between the above points was 180 miles, and over 
a rough and difficult region; by his railroad route it is 80 miles. For 35 miles the line is nearly 
level; for the remaining 45 miles there is a uniform grade of about 70 feet. During the whole 
distance there is scarcely an irregularity upon the surface of the ground. 
The department of natural history was under the charge of Dr. Newberry, whose name is 
well known in connexion with such labors. His eminent fitness for the position will appear by 
an examination of what he has accomplished. His report upon the geology of the region 
traversed, I regard as the most interesting and valuable result of the explorations. In making 
the collections Dr. Newberry was zealousy assisted by Mr. Mollhausen, who also prepared the 
greater portion of the views and illustrations taken during the trip. 
The accompanying maps were made by Mr. Egloffstein, who went out with me as topographer. 
Some of the views, it will be perceived, are also from his pencil. The maps have been drawn 
directly upon the plates, which will obviate the ordinary expense for engraving. The style 
is partly new. The system of light and shade has been frequently adopted; but the applica- 
tion of the ruled tints—by which the light sides of the mountains are relieved, and the com- 
parative altitudes of different levels exhibited—is original, I believe, with the artist. The 
beautiful and effective representation of the topography is the best encomium both upon the 
style and its projector. The privation and exposure to which Mr. Egloffstein freely subjected 
himself, in order to acquire topographical information, has resulted in an accurate delineation 
of every portion of the region traversed. 
The survey of the navigable portion of the river was principally conducted by Mr. C. 
Bielawski, of San Francisco. The duties of meteorologists and assistant topographers were 
faithfully performed by Messrs. Taylor and Booker. 
To Mr. Carroll, the engineer and constructor of the steamer, and to the pilot, Captain 
Robinson, are due, in great measure, the successful ascent of the Colorado. The report shows 
how large a share they had in the accomplishment of the work. 
The mule train, while following the bank of the river and crossing the country, was in 
charge of Mr. G. H. Peacock, of California, whose good care and experienced management 
conducted it safely over as difficult a country as can perhaps be found upon any portion of the 
continent. 
To Lieutenant Tipton, 3d artillery, who commanded the escort, I feel myself under many 
obligations for voluntary and important assistance rendered in the astronomical and meteoro- 
_ Jogical departments, for the excellent order and discipline maintained throughout the trip 
among the individuals of his command, and for the uniform cordial co-operation which con- 
tributed so much to the pleasure and success of the expedition. 
Tam, sir, very respectfully, your obedient servant, 
¥ - J.C. IVES, 
First Lieutenant Top. Engineers, Com’g Colorado Exploring Expedition. 
A. A. Hompureys, Captain Top. Engineers, 
In charge of Office of Explorations and Surveys, War Department, 
