BULLETIN No. 3 17. 



MAY, 1915 



Meteorological Observations 



AT THE 



MASSACHUSETTS 



AGRICULTURAL EXPERIMENT 



STATION. 



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



Height of barometer above ground, ^ I ft. Above sea level, 2yj.^ ft. 

 Height 0/ Wind Instruments 72 ft. 



MONTHLY SUMMARY. 



Pressure. In inches. 



Maximum reduced to freezing, 29.98. nth, 10 P. 

 Minimum reduced to freezing. 29.16, 4th, 3 p. 

 Reduced! maxinuim reading, 30.2S, nth, 10 p. 

 Reducedt mininuiin reading, 29.45, 4th, 3 P. 



Mean semi-daily reduced, 29.905 



Monthly range, 0.83 



*Air Temperature. In Degrees Fahr. 



Highest So.o. 31st, 6p. 



Lowest 34-0. i6th, 5:30 a. 



Mean hourly, 54.1 



Mean of means of max. and min 53.8 



Mean sensible (wet bulb), 48 7 



Monthly range 46.0 



Higliest mean daily, 63.4, Sth 



Lowest mean daily, 44-6. ist 



Mean maximum, 65.4 



Mean minimum 42.2 



Mean daily range, 23.2 



Greatest daily range 43-';. 3ist 



Least daily range, 3-G. i7th 



Humidity. 



Mean dew point, 4'?-3 



Mean force of vapor 430 



Mean relative humidity, 66.8 



Precipitation. In inches. 



Total precipitation, 1.20 



Number of days on which .01 inch or more 



rain fell 11 



♦Temperature in ground shelter. 

 I Reduced to freezing and sea-level. 



Wind. 



Total movement 4087m. 



Greatest daily movement 343m., 27th 



Least daily movement, 15m., 2d 



Mean daily movement, 132 m 



Mean hourly velocity, 5-5 m. 



Maximum pressure per square foot, 8.5 lbs.= 



41m. per hour, 9th, 9P., W.N.W. 

 Maximum velocity for 5 minutes, 27m. per 



hour, 26th, gp., N. 

 Prevailing Direction. West Northwest. 



Summary. 



North Northwest 13 per cent. 



West Southwest 10 " 



West 13 " " 



South 13 " " 



Northwest 10 " " 



West Northwest i3 " " 



Other directions 28 " " 



Weather. 



Mean cloudiness observed, . . . .46 per cent. 

 Total cloudiness recorded by the Sun Ther- 

 mometer, . . . iSo hrs. = 40 per cent. 



Number of clear days 11 



Number of fair days 14 



Number of cloudy days, 6 



Bright Sunshine. 



Number of hours recorded. . . 273 

 Rain, ist, 2d, 4th, 5th, 7th, 8th, 



17th, 2ISt, 22d, 24th, 26th. 



Thunder and Lislitning, 21st. 

 Frosts, 15th, i6th, 20th. 

 Gales, 35 or more miles per hour : 

 S ; 41m., 9th, W.N.W.; 78m , 



lirs = 6o^. 

 :3th, i6th. 



39m., 7th, 

 26th, N.; 



39m., 27th, N.W.; 40m., 2cSth, W.N.W. 



