BULLETIN No. 396. 



DECEMBER. 192 1 



Meteorolooical Observations 



AT THE 



MASSACHUSETTS 



AGIMCULTUIUL EXPElilMENT 



STATION. 



Latitude, 42° 23' 48.5" N. Longitude 72* 31' 10" \V. 



Height of ha fo meter above ground, 51 ft. Above sea level, 2jj.^ ft. 

 Height oj Wind Instruments J 2 ft. Time used, "j^th Mer. 



MONTHLY SUMMARY. 



-Pressure. In inches. 

 Maximum reduced to freezing, jo. 46, i6th, 10 A 

 Minimum reduced to freezinji;, 29.05, 12th, 4 p 

 Reduced maximum reading 30.79 i6th, 10 .\ 

 Reduced minimum reading, 29.36, 12th, 4 p 



Mean semi-daily reduced 30.005 



Monthly range 1.43 



Air Temperature. In Degrees Fahr. 



Highest 57.0, iSth, 7:00 a 



Lowest -i.o, 22d, 7:3oA 



Mean hourly 25.7 



Mean of means of max. and min. .... >>5.8 



Mean sensible (wet bulb) 22.'', 



Monthly range 58. 



Highest mean daily 46.0. iSth 



Lowest mean daily 6,7, 30th 



Mean maximum 31.4 



Mean minimum 17.1 



Mean daily range 17.3 



Greatest daily range 31.0 21st 



Least daily range 5.5, 25th 



Humidity. 



Mean dew point 17.7 



Mean force of vapor 0.143 



Mean relative humidity 



Precipitation. In inches. 



Total precipitation, in inches 1.90 



Number of days on which .01 inch or more 



rain fell 



Total .Snow in inches 



Days of sleighing 



•Temperature in ground shelter. 

 "Reduced to freezing and sea-level. 



Wind. 



Total movement ^704 m 



Greatest daily movement 461m, iSth 



Least daily movement 21 m, 5th 



Mean daily movement 152m 



Mean hourly velocity 6.3m 



Maximum pressure per square foot, 29 lbs = 



76m per hour, 18th, 5 A, W.S.W. 

 Maximum velocity for 5 minutes, 36m per 



hour, iSth, 7 A, W.S.W. 

 Prevailing direction. West Northwest. 

 Summary. 



North 16 per cent 



North Northeast 10 " " 



West Northwest 19 " " 



South Southwest 10 " " 



Northwest 16 " " 



Other directions 29 " " 



Weather. 



Mean cloudiness observed .... 45 per cent 

 Total cloudiness recorded by the Sun 



Thermometer . . 131 hours = a6 per cent. 



Number of clear days 14 



Number of fair days 5 



Number of cloudy days 12 



Bright Sunshine. 



Number hours recorded, 152, = 54 per cent. 

 Rain, 2d, I2th, 17th, 18th, 

 Snow, 12th. l6th, 2ist, 23d. 24th, 29th. 

 Gales, 54m, 3d. W. N.W.: 40m, 6th, W. N.W. 



40m., 7th, W. N. W.; 76m., i8th, W.S.W.: 



3Sm., 19th, W. N. W.: 47ni.. 21st, W. 



N. W.: 35m. 22d, N. W. :36m. 29th. N 



N.W.: 39m., 30th, N. 



