TABLES OF DIFFERENCES OF MEAN TEMPERATURES. 161 



Sierra Madre, on the west by the Sierra Nevada and including the regions of the 

 Colorado River, also the northern portion of the Eio Grande, furnishes many 

 interesting examples of an excessively large daily range, the magnitude of which 

 may, in a measure, be inferred from the following comparisons of the difference of 

 temperature at the observing hours 7 A. M. and 2 P. M., or at the time of sunrise 

 and 3 P. M., for a few selected places, located in New Mexico, Texas, Arizona, and 

 California. With the exception of Fort Yuma, which is but 200 feet above the 

 sea level, these stations are all at considerable elevations. 



Average difference in the temperature, between sunrise and 3 P. M., or between 

 7 A. M. and 2 P. M., taken from the monthly means at these hours of observation. 

 [Army Met. Regs, for 1855 and I860.] 









c 



u 



§ 













Name of Station, 





& 



g 



a 



-a 



.^ 



B 



•0 







State, 

 or Territo 







3 

 "gH 



P. a 



PQ.2 



0^ 



"gu 



y. 









fe 



< 



[X, 



p^ 



h 



t^ 



Ph 



fe 







Latitude . . . 



32<'4o' 



35°o6' 



3o°45-' 



3S°43' 



3i°4o' 



33°36' 



32°46' 



3i°58' 



4i°o7' 



TJ 



Longitude . . . 



107 09 



106 38 



105 00 



109 10 



no 55 



107 00 



114 44 



100 15 



121 29 





Altitude (feet) . 



4500 



5032 



3710 



6500 



5330 



4576 



200 



2120 



3390 



•^1 

 ^ 



No. of years 1 

 of record ) ' 



4 



7 



I 



7 



2 



4 



7 



7 



2 



January . . . 



26° 



27° 



37° 



24° 



27° 



26° 



22° 



23° 



15° 



24° 



February 







31 



26 



35 



23 



28 



28 



25 



24 



13 



25 



March . 







30 



31 



41 



25 



32 



27 



24 



26 



16 



27 



April . 







34 



31 



30 



25 



29 



29 



24 



26 



24 



28 



May 







36 



34 



29 



24 



25 



22 



22 



19 



20 



25 



June 







34 



29 



21 



27 



23 



22 



22 



20 



21 



25 



July. . 







27 



25 



13 



19 



'3 



20 



20 



20 



25 



21 



August . 







25 



26 



17 



19 



15 



17 



20 



20 



29 



21 



September 







25 



28 



14 



25 



17 



17 



20 



18 



29 



22 



October 







32 



27 



17 



28 



22 



21 



21 



21 



31 



25 



November 







33 



26 



29 



24 



23 



22 



20 



24 



17 



24 



December 







25 



22 



30 



22 



21 



23 



18 



23 



12 



21 



Year . . . . 



30 



28 



26 



24 



23 



23 



22 



22 



21 



24 



The mean daily range, for any month or for the year, at any of the above stations 

 is necessarily several degrees higher than the corresponding tabular difference 

 since the morning and afternoon extremes do not take place at the hours of 

 observation ; even the tabular numbers, when contrasted with the observed daily 

 range in other parts of the United States, appear excessive, and imperfect as they 

 must be owing to the short number of years and the great variability of the quan- 

 tities themselves, the annual fluctuation of the differences given in the last column 

 presents quite a regular double crested curve. The maximum daily range occurs 

 in March and April, a second smaller maximum in October with minima in July 

 and August, and again in December, the latter minimum being apparently a com- 

 mon feature within the boundaries of the United States. The great development 

 of the daily fluctuation at Albuquerque, N. M., would recommend this station as a 

 suitable locality for an extended hourly series (to be recorded with a self-registering 

 instrument). Such observations would greatly assist in establishing corrections to 



21 February, 1875. 



