BULLETIN No. 247. 



JULY. 1909. 



Meteorological Observations 



AT THE 



MASSACHUSETTS 



AGRICULTURAL EXPERIMENT 



STATION. 



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



Height of barometer above ground, ^r ft. Above sea level, 2'J3.§ ft. 

 Height of Wind Instruments 72 ft. 



MONTHLY SUMMARY. 



Pr«»»\ire, In inclies. 



Maximum reduced to freezing, 29.97, 21st, 6 a. 

 Minimum reduced to freezing, 29.10, 3d, 5A. 

 Reducedl maximum reading, 30.27, 21st, 6 A. 

 Reduced! minimum reading, . 29.39, 3d, jA. 



Mean semi-daily reduced, 29.914 



Monthly range, 0.88 



* Air Temperature. In Degrees Fahr. 



Highest 93.0. 30th, 4 P. 



Lowest 420, 9th, 5 A. 



Mean hourly, 68.7 



Mean of means of max. and min., .... 68.9 



Mean sensible (wet bulb), 62.5 



Monthly range, S'-o 



Highest mean daily 80.8,30th 



Lowest mean daily, 61.8,4th 



Mean maximum 81.9 



Mean minimum, 55-9 



Mean daily range 26.0 



Greatest daily range, 40-o. 9th 



Least daily range 8.5,23d 



Humidity. 



Mean dew point, 58.6 



Mean force of vapor 708 



Mean relative humidity 71 



Precipitation. In inches. 



Total precipitation 2.24 



Number of days on which .01 inch or more 

 rain or melted snow fell, • 6 



Wind. 



Total movement, 5097ni. 



Greatest daily movement, . . . .294m., nth. 



Least daily movement 64m., 21st. 



Mean daily movement i64ni. 



Mean hourly velocity 6.8 m . 



Maxinmm pressure per square foot, 7.0 lbs.= 



37 m. per hour, i8th, 6p., N. 

 Maximum velocity for 5 minutes, 28m. per 



hour 8th, 5 p., N. 

 Prevailing Direction, West. 



Summary. 



Southwest 26 percent. 



West Northwest 16 " " 



North Northwest 13 " " 



Northwest 10 " " 



Other directions, 35 " " 



Weatlier. 

 Mean cloudiness observed, . ■ . .33 per cent. 

 Total cloudiness recorded by the Sun Ther- 

 mometer, i72hrs.=37 per cent. 



Number of clear days, 4 



Number of fair days, 24 



Number of cloudy days, 3 



Bright Sun$hine. 



Number of hours recorded, . . 290 hrs.=635 

 Rain. 2d, 3d, 5th, 6th, 13th, i6th, 18th, 

 23d, 24th. 



Thunder and Lightning:, i6th, 23d. 

 Gales, 35 miles or more per hour ; 35m. 

 3d, N.W. ; 36ni. 5th, N. ; 37m. 8th, N. 



" Temperature in ground shelter, 

 t Reduced to freezing and sea-level. 



