BULLETIN No. 348. 



DECEMBER, 1917 



Meteorological Observations 



AT THE 



MASSACHUSETTS 



AGllICULTURAL EXPERIMENT 



STATION. 



Latitude, 42" 23' 48.5" N. Longitude 72' 31' 10" W. 



Height of barometer above gron/iif, 5^ ft- Above sea level, 2jj.^ ft. 

 Height oj Wind Iiistruiiients ^2 ft. 



MONTHLY SUMMARY. 



Pressuie. In inches. 

 Maximum reduced to treezing,3o.53, 17th, 10 A 

 Minimum reduced to freezing, 2S.S9, 9th, 2 a 

 Reduced maximum reading, . . 3o.S6,i7th,io A 

 Reduced! minimum reading, . 29.20, 9th, 2 A 



Mean semi-daily reduced 30.222 



Montlily range 1.66 



*Air Temperature. In Degrees Fahr. 



Highest 40 5, 5th, 3:30 p 



Lowest -22.5, 30th, 7:30 A 



Mean hourly 16,9 



Mean of means of max. and min 17.1 



Mean sensible (wet bulb) 14 ? 



Monthly range 63.0 



Highest mean daily 33.3, ist 



Lowest mean daily -12.7,30th 



Mean maximum 26.5 



Mean minimum 7. 



Mean daily range 1S.8 



Greatest daily range 29.0, 22d 



Least daily range 5.0,20th 



Humidity. 



Mean dew point 9.3 



Mean force of vapor 104 



Mean relative humidity 76.9 



Precipitation. In inches. 



Total precipitation, in inches 2.56 



Total snow, in inches 14J 



Number of days on which .01 inch or more 



rain fell 5 



Days of sleighing, ... 31 



•Temperature in ground shelter. 

 ••Reduced to freezing and sea-level. 



Wiud. 



Total movement 4897 m 



Greatest daily movement 43Sm, 2d 



Least daily movement ';m, i6th 



Mean daily movement 158.0 m 



Mean hourly velocity 6.6 m 



Maximum pressure per square foot, 9.0 lbs = 



43m per hour, 14th, 4 p, W.N.W. 

 Maximum velocity for 5 minutes 24m per 



hour, 14th, 4 p, W.N.W. 

 Prevailing direction. West Northwest. 



Summary. 



North 42 per cent 



North Northwest 13 " 



-South Southwest 13 " 



Northwest 10 " 



West 10 " 



Other directions 12 " 



Weather. 



Mean cloudiness observed .... 46 per cent 

 Total cloudiness recorded by the Sun 



Thermometer . . 147 hours = 45 per cent 



Number of clear days . 9 



Number of fair days 10 



Number of cloudy days 12 



Bright Sunshine. 



Number hours recorded, 156 hrs, = 55 per cent. 



Koin. ist, 24th. 



Snow, ist, Sth,l0th, 13th, 14th, 28th. 



Gales, 35 or more miles per hour. 35m, 2d, 



N.N.W.; 40m, 9th, W.N.W.; 3£m, 10th, 



W.N.W,; 43m, 14th, W.N.W. 



