TO THE COPPER MINES. , 201 
distance. The line passed directly over this, and a 
monument upon it would be seen for a great distance 
in every direction. 
April 24th. The day having arrived upon which 
it was agreed that the Initial Point, where the southern 
boundary of New Mexico intersects the Rio Grande, 
should be established, the documents signed, and the 
point marked, it seems proper that I should briefly 
relate the history of this important portion of my duties 
as Commissioner under the 5th Article of the Treaty of 
Guadalupe Hidalgo. : 
Under the date of December 3d, 1850, I spoke of 
the meetings of the Joint Commission, and of the 
difficulties that lay in the way of a speedy agreement 
as to the boundary between the Rio Grande and the 
Gila, in consequence of two gross errors in the map to 
which the Commissioners were confined by the treaty. 
It was discovered that the Rio Grande was laid down 
on this map, more than two degrees too far to the 
eastward—the river, where it is intersected by the 
southern boundary of New Mexico, being really in 
106° 40’ west longitude, instead of 104° 40’. The 
other error was in the position of the town of El Paso, 
which appears on this map to be but seven or eight 
minutes below the 32d parallel, while its actual distance 
is thirty minutes furthersouth. After several meetings, 
involving much discussion, the Joint Commission agreed 
to fix the Initial Point on the Rio Grande at the latitude 
given by the map, without any reference to its distance 
from El Paso; and to extend it westward from that 
point three degrees, without reference to where the 
line so prolonged should terminate. This being agreed 
