30 
CLIMATE—ON THE SUPPLY OF WATER. 
Section 2. CLIMATE. 
The climate of the interior section is delightful throughout the year ; its seasons are 
two, the dry and the rainy—the former corresponding to our autumn, winter, and spring, while 
the rains occur during the summer months. This arrangement is just the reverse of what 
obtains in California. The air of the winter months is elastic and bracing, while the rains 
temper the heat of midsummer. The temperature along the lower Gila is intense during the 
summer months. The thermometer, in camp, near its mouth, indicated a mean temperature 
for June, 1855, 91°.1, the maximum being 106.°2 ; and at the Maricopa wells, for four and a 
half days (June 28 to July 1st) the mean temperature was 98°.8, the maximum being 112°. 
Below the Pimas villages, on July 2, the mean temperature was 101°.9, the maximum being 
112°. On the day of our arrival at Fort Yuma, the thermometer at the fort indicated 119°; the 
greatest degree of heat is felt while traversing the western slope, but it is very sensibly reduced 
as soon as the plateau is ascended. During the reconnaissance of 1854 the thermometer stood 
below the freezing point at Tucson, Rio San Pedro, Valle del Sauz, and at the Rio Mimbres ; 
and at the same points, at 3 or 4 p. m., it stood, respectively, 65°, 68°, 78°, 61°. While in 
camp, at nearly the same localities, during the months of July and August, it ranged at sunrise 
asfollqws: 57°.5, 68°.5, and at 3 p. m. 100°, 98°.5, and about 96°. 
When we take into consideration the construction, maintenance, and after-working of a rail¬ 
road, the climate is favorable ; for working parties can remain in the field throughout the year, 
and the daily evolutions of the train will never be interrupted by snow or ice. The above indica¬ 
tions of temperature for the summer season may seem to refute the assertion with regard to 
working parties being employed throughout the year, but it should be borne in mind that, on 
these elevated plateaus, the atmosphere is remarkably dry ; the difference between the wet and 
dry bulb thermometer often indicating more than 30°, and consequently one never feels that 
sultriness which so often accompanies high temperatures in the Mississippi valley and on the 
Atlantic slope. The exhilerating effect of a New Mexican climate is duly attested by almost 
every person who has experienced it from their often expressed anxiety to return to that region. 
Section 3. WATER 
The supply of water upon the plateau is limited. Along and near the proposed line 
it is found at the following localities, and from these the working parties can be supplied: 
At Neide’s spring, at the southwest corner of the basaltic hills, east of Cooke’s spring; Cooke’s 
spring; Rio Mimbres; Agua Fria; Ojo de la Vacca; Ojo de Inez; Valle del Sauz; in the 
Puerto del Dado ; Croton springs at the Playa de los Pimas ; Castro spring, near the Railroad 
Pass under Mount Graham ; Pheasant creek; Antelope and Dove springs at the base of the 
Calitro mountains ; and at Bear springs at the head of the Aravaypa. The distances, in direct 
lines, from one of these localities to another, are as follows : 
Miles. 
From the Rio Grande to Neide’s spring... 40 
From Neide’s spring to Cooke’s spring... 12 
From Cooke’s spring to Rio Mimbres. 21 
From Rio Mimbres to Agua Fria. 15 
From Agua Fria to Ojo de la Vacca. 6 
From Ojo de la Vacca to Ojo de Inez. 12 
From Ojo de Inez to Valle del Sauz. 40 
From Valle del Sauz to Puerto del Dado.. 23 
Miles 
From Puerto del Dado to Castro spring... 3 > 
From Puerto del Dado to Croton springs. 30 
From Castro spring to Croton springs. 18 
From Croton springs to Pheasant creek.. 12 
From Pheasant creek to Antelope spring. 3 
From Antelope spring to Dove spring. 2J, 
From Dove spring to Bear spring.. 16 
