84 



active in the Arkansas Valley, where the area brought under ditch 

 aggregates some 700,000 acres. It is estimated that the total area under 

 ditch in Colorado at the end of 1890 was 6,337 square miles, or 4,008,409 

 acres; the area irrigated, 1,035,000 acres. The mileage of canals was 

 6,317, not including numerous short ditches in the mountain regions. 

 The cost of irrigation works in Colorado is roughly estimated at 

 $10,980,000. 



Irrigation literature. — A list of 71 works bearing on the subject of 

 irrigation, with brief comments on tbe character and scope of each. 



Meteorological observations. — Tabulated data are given of the monthly 

 precipitation at the station for 14 years (1872-90), and for twenty local- 

 ities in the State for 1890; daily observations of the dew-point and rel- 

 ative humidity for each month of 1890; the monthly evaporation at tlie 

 station and at the San Luis and Kocky Ford substations ; monthly and 

 daily observations of tlie sunshine in hours and miuutes for 1890 at the 

 three stations; daily actinometer readings from April 1 to November 

 12, 1890, inclusive; daily thermometer readings and range of tempera- 

 ture for each month of 1890; daily terrestrial radiation; thermometer 

 readings for each' month of 1890; and the means of two daily readings 

 of the barometer for each month of 1890. 



Annual summary of meteorological observations for 1800. 



Stations. 



pressure. 



Fort Collins. 

 Del Norte... 

 Rocky Tord. 



Inchr" 

 2.5. OIU 

 22. &14 



Air temperature (degrees F.). 



Hieheat 



95.3 

 89 

 10-1 



Lowest. 



Moan. 



-20 49.08 

 -16 44.80 

 -10 50.7 



Mean daily 

 rant;e. 



31.33 

 32.12 



Greatest 

 daily 

 range. 



48.09 



No. of days 

 ininhnuni 

 tenijiera- 

 turi" be- 

 low 32° F. 



1G8 

 217 

 147 



Stations. 



Fort Collins .. 



Del Norte 



Kocky Ford .. 



Humidity. 



Mean 

 dew- 

 point. 



40.19 

 ^2. 12 

 42. 73 



No. of 

 Mean 'days on 



relative 

 humid- 

 ity. 



62.48 

 73.37 

 71.0 



whirh 

 dew 

 was ob- 

 served. 



Wind. 



Prevail- 

 ing 

 direction. 



WandSW. 

 W. 

 W. 



Maxi- 

 mum 

 veloci- 

 ty per 

 hour. 



Milet. 

 70 



Precipitation. 



Total 

 precipi- 

 tation 



(-..lin 



and 

 melted 

 snow). 



Tnche*. 

 11.435 



8.77 

 6.93 



Total 

 snow 

 fall. 



Tnchet. 

 17.8 

 24.75 

 14.5 



No. of days 

 on V liich 

 01 inch of 

 rain or 

 melted 

 snow fell. 



Sunshine. 



Per 



cent. 



56 65.1 



41 



27 I 71.4 



Tofcil 

 hours. 



2,798 



Soil tenqyeratures. — A tabular record of the weekly means of soil tem- 

 peratures at depths of from 3 to 72 inches for three sets of soil ther- 

 mometers placed in soils varying in elevation and moisture. 



Rei'ort of grass station, C. S. Crandall, M. S. (pp. 156-183). — 

 This is a first year's report of experiments, conducted under the tlirec- 

 tiou of the Division of Botany of the U. S. Department of Agriculture, 



