1891.] 



PUBLIC DOCUMENT — No. 4. 



xni 



Meteorological Observatory of the Hatch Experiment Station, 

 Massachusetts Agricultural College, Amherst. 



Latitude, 42° 23' 48.5" N. Longitude, 72* 31' 10" W. Height of instruments above ground, 

 51 feet. Above sea level, 260 feet. 



Annual Summary foe 1890. 



Pressure. 

 [In Inches.] 

 Actual maximum, reading, 30.64, Jan. 1,1 A. 

 Actual minimum, reading, 29.025, Oct. 27, 2p. 

 Mean reduced to sea level, . . 30.03 

 Annual range, 1.615 



Highest, 

 Lowest, 

 Mean, . 

 Annual range, 

 Highest mean daily, 

 Lowest mean daily, 

 Mean maximum,. 

 Mean minimum, . 

 Mean daily range, 

 Greatest daily range, 

 Least daily range, 



* Air Temperature. 

 [In Degrees Fahr.] 

 92 



2; -6 



84; 



38; 48 

 2 Feb. 28, 5 



94, July 8 

 5, March 7 

 47.7; 46.9 

 90; 100.5 

 81 July 31 

 83 Dec. 30 

 54.3; 57.7 

 37.4; 35.9 

 16.8; 21.9 

 .5 April 13 

 .5 April 27 



Humidity. 



Mean dew point 40.6 



Mean force of vapor, 4378 



Mean relative humidity, . . . 71.1 



Wind. 

 [Prevailing Directions.] 



North, 15# 



South 11# 



North-west, 11$ 



South, south-west, .... 10$ 

 Total movement, . . . 54,684 m. 



Greatest daily movement, . 410 m. April 5 

 Least daily movement, . 18 m. Feb. 25 

 Mean daily movement, . . 149.6 m. 

 Mean hourly velocity, . . 6.2 m. 



Maximum pressure per square foot, 27J 

 lbs. = 74 m. per hour, Jan . 8, 3 A.M. 



* Precipitation. 

 Total rainfall or melted snow, 39.48 in., 



48.5 in. 

 Number of days on which .01 of rain or 



melted snow fell, .... 141 



Total snow fall, in inches, . . 43£ 



Weather. 



Mean cloudiness observed, . . 57# 



Total cloudiness recorded by the sun ther- 

 mometer, 2,279 hours, or 51$. 



Number of clear days, . . . 137 



Number of fair days, . . . 105 



Number of cloudy days, . . . 123 



Bright Sunshine. 

 Number of hours recorded, 

 Mean ozone, .... 



2,194 



3S* 



Last, 

 First, 



Last, 

 First, 



Dates of Frosts. 



Dates of Snow. 



May 12 

 Sept. 25 



April 8 



Oct. 19 



Twenty -eight halos were observed ; 79 per cent were accompanied by storm within twenty- 

 four Lours, and 61 per cent within forty-eight hours after the occurrence of the halo. 



The rainfall was a trifle above the average for fifty years, as recorded at Amherst College. 

 The temperature was also above the mean for the same time. 



C. D. Warner, Meteorologist. 

 A. T. Beals, Assistant. 



*The first figures denote readings at top of tower, the second at base. 



