544 RESULTS OF THE LABORS 
of this hitherto unknown region, were accurately deli- 
neated upon the maps. 
The barometrical profiles constructed by Lieut. 
Whipple, and the minute topography of the maps laid ° 
down in the two extensive journeys in which this 
officer accompanied me between the Rio Grande and 
the Pacific, are of the highest importance as showing 
the practicability of a route for a railroad or other 
public highway south of the Gila. In order to render 
this information immediately available, a reduction of 
the astronomical and meteorological observations has 
already been made, as well as barometrical profiles of 
these several reconnoissances. 
The surveys of Mr. Gray and Lieutenant Whipple, 
and the astronomical observations made by the latter 
in the journeys to and from California, have enabled 
the Commission to lay down with accuracy for the first 
time the geography of the Gila and of the vast region 
between the Rio Grande and the.shores of the Pacific. 
The plot and topographical sketches of the survey 
between the Rio Grande and the Colorado were mostly 
completed in California and transmitted to Washing- 
ton. At the same time reports of various reconnois- 
sances made along the line, with tables of astronomical, 
magnetic, and meteorological observations by Lieut. 
Whipple were forwarded. These plottings, reports, 
and tables were placed by me in the hands of Major 
Emory, Principal Surveyor, on my return to Washing- 
ton; and engineers and draughtsmen have since been 
engaged in completing the maps, and reducing the 
observations, under his direction. 
8. Along this line an extensive series of sketches 
