8 BULLETIN 1233, U. B. DEPARTMENT OF AGRICULTURE. 



To make the records as free as possible from purely local influences, 

 all atmospheric conditions have been observed on a tower so con- 

 structed that the thermometers, anemometers, evaporimeters, and 

 other apparatus could be placed about 20 feet above the ground. (See 

 PI. I, fig. 1.) At this height no artificial influence acts upon any of the 

 instruments, and even the nearest trees are too distant to have any 

 appreciable effect upon wind movement or direction, although both 

 movement and direction are strongly influenced by the configuration of 

 the larger valley in which this small ridge lies. In 1917 a house was 

 erected about 30 feet to the northwest of the tower, with the roof 

 comb slightly higher than the instruments on the tower; but no effect 

 from this structure has been noted in any of the records, and it is not 

 thought that an appreciable effect can be produced by it, either 

 upon temperature or wind movement. 



In addition to the records obtained on this tower, it was thought 

 desirable, in 1916, to measure air temperatures near the ground, as 

 was being done at many of the outlying stations, in order that knowl- 

 edge might be had as to the influence of elevation on temperatures. 

 These ground temperatures go under the station number 1-G to dis- 

 tinguish them from the records designated 1-A. The equipment of 

 this station, where most of the observations have been continued to 

 date, has been as follows: 



Tower (F-1A) : 



Maximum and minimum thermometers, in standard shelter. Standardized 

 U. S. Weather Bureau instruments used, January, 1910/ to April, 1920. 



Air thermograph, March, 1910, to April, 1920* 



Anemometer, standard, with register, February, 1910, to date. 



Wind vane, with register, February, 1910, to date. 



Sunshine recorder, electric themometric, with register, February, 1910, to date. 



Psychrometer, January 21, 1910, to April, 1920. 



Evaporimeter, inner-cell, Type 2, March 22, 1916, to January 1, 1917; inner- 

 cell, Tvpe 4, January 1, 1917, to date. 

 Ground (F-1G): 



1-foot soil thermometer, in iron pipe, February 10, 1910, to September, 1918. 



2-foot soil thermometer, in iron pipe, February 10, 1910, to June 30, 191-1. 



4-foot soil thermometer, in iron pipe, July 1, 1914, to date. 



1-foot soil thermometer, in wooden tube, February 20, 1918, to June 10, 1920. 



Maximum and minimum thermometers, on shielded board, April 1, 1916, to 

 February 20, 1918. 



Maximum and minimum thermometers, in standard shelter, February 20, 191S, 

 to September, 1918. 



Air thermograph, in standard shelter, February 20, 191S, to September, 191S. 



8 and 12 inch rain gages, with register, January, 1910, to date. 



Soil well in operation from June 29, 1914, to 1918. Determinations of moisture 

 during growing season at depths of 1, 2, and 3 feet, and for 1917 at surface. 



No records whatever for any of the above-described equipment were 

 obtained during the periods from January 21 to March 20, 101 1; from 

 December 11, 191 b to February 28, 1915; and from September 21. 

 1918, to May 1, 1919. For some conditions, the record obtained up 

 to 10 is seems adequate for establishing practically normal values; 

 for others, the two succeeding years introduce very different values, 

 and their records are therefore used. 



0-1: Colorado Springs plains. — Elevation, 6,098 feet. On flat 

 plains about loo feel higher than the valley of Monument Creek, 



immediately adjacent on t be west. The observations here were taken 

 on the r(H>\' of one of the buildings on the campus of Colorado College, 



{tossibly 50 feet above the ground. The building is practically on the 

 >reak between (lie flat plains which lie to the cast and the valley of 



