io The Colorado Experiment Station. 
been applied. Our precipitation nearly always comes with a rising 
barometer. When the barometer is very low it is nearly always 
succeeded by wind. The precipitation is preceded by any barometer 
from the moderately low to the high. 
The average date at which the last killing frost is likely to occur 
in a locality as a normal event, must often determine the limit in 
latitude and altitude at which a fruit or certain kinds of crops can be 
grown. Even in the most favored fruit regions of the State the 
records bring out the fact that killing frosts may be expected and 
will occasionally do great damage, though the smudge pot is lessen¬ 
ing the danger and making a certainty of many years that formerly 
would have proved a total loss of crop. At Fort Collins the average 
date is May ioth to May 15th and September 15th to 20th. At 
Rocky Ford and Cheyenne Wells the season is a little longer. 
In reporting the meteorological observations for the last twen¬ 
ty-five years it has been thought well to include, for purpose of com¬ 
parison, the records taken for temperature and rainfall for our sub¬ 
stations, and also the precipitation from a number of stations scat¬ 
tered over the State. Some of these observers reported to this Sta¬ 
tion during the early years, but during the last few years have re¬ 
ported altogether to the United States Weather Bureau office in 
Denver. They have been included here that they may be accessible 
along with data from our Station to people who may be interested. 
The Agricultural Experiment Station at Fort Collins is located 
at the base of the Rocky Mountains, about four miles from the low¬ 
est foothills, beyond which the mountains rise to the summit of the 
range about fifty miles westward. It is located in Larimer county, 
about seventy-five miles north of Denver, on bench land about one 
mile south of and forty feet above the Cache la Poudre river. The 
College is in an irrigated area which extends about three miles fur¬ 
ther west, while in all other directions there are irrigated lands for 
a number of miles. The nearness to the mountains affects the cli¬ 
mate in the amount and character of the clouds, in the temperature 
and in the diiection and character of the winds. The elevation is 
about 5,000 feet, the latitude 40° 34', and the longitude 105° 6' 
west of Greenwich. 
The maximum and minimum thermometers used are called self- 
1 egistei ing, that is, the maximum thermometer registers the warm¬ 
est temperature of the day and the minimum the coldest and the ther¬ 
mometers remain at the extreme point until read and reset. They 
are read each day so that a continuous record of the lowest and high¬ 
est temperature for each day of the year is kept at each station. The 
difference between the maximum and minimum temperatures <jf the 
day constitutes the daily range of temperature. The average of the 
two gives the mean temperature. The difference between the hDh- 
