542 RESULTS OF THE LABORS 
Graham, a party under the charge of John Bull, Esq. first 
assistant surveyor, made a reconnaisance of the coun- 
try between the Rio Grande and the Gila, in which a 
more direct road was opened from Dofia Ana to the 
Copper Mines. This reconnaisance was extended to 
the Presidio of Janos, in the State of Chihuahua. 
5. The southern boundary of New Mexico, ex- 
tending west three degrees from the Initial Point on 
the Rio Grande at 32° 22” north latitude, and from 
the western termination of the line due north to the 
Gila, was surveyed exclusively by Lieutenant A. W. 
Whipple and his assistants. This officer also surveyed 
the river Gila, from the point where it is intersected 
by the before-mentioned line to its junction with the 
Colorado, a distance, including the sinuosities of the 
river, of about four hundred and fifty miles, making 
together between six and seven hundred miles from 
the Rio Grande to the Colorado. The boundary 
along this parallel was the most difficult part of the 
whole survey. 
Astronomical observations were made during the 
survey of the Gila every night but two, which were 
cloudy. The whole number of astronomical and me- 
teorological stations was about sixty; nearly all of 
which were also magnetic stations. To these it is 
proper to add that there were three astronomical and 
magnetic stations, besides several made by Lieutenant 
Whipple on his trip from San Diego to the Colorado, 
in September, 1849, thus completing a consecutive 
chain of points of observation by this officer extending 
from the Atlantic coast, via San Antonio, El Paso del 
Norte, and the mouth of the Gila, to the Pacific Ocean. 
