BULLETIN No. 343. 



JULY, 1917 



Meteorological Observations 



AT THE 



MASSACHUSETTS 



AGRICULTURAL EXPERIMENT 



STATION. 



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



Height of barometer above ground, 31 ft. Above sea level, ^73-5 f^- 

 Height of Wind Instruments J 2 ft. 



MONTHLY SUMMARY. 



Pressure. In inches. 

 Maximum reduced to freezing, 29.93, 25th, 8 a 

 Minimum reduced to freezing, 29.36, 12th, 4 a 

 Reducedt maximum reading, 30.22, 25th, 8 a 

 Reducedt minimum reading, 29.66, 12th, 4 a 



Mean semi-daily reduced 29.948 



Montlily range 0.56 



*Alr Temperature. In Degrees Fahr. 



Highest 98.C;, 31st, 5 P 



Lowest 51.5,6th, 5 A 



Mean hourly 71.7 



Mean of means of max. and min 72.5 



Mean sensible (wet bulb) 66 2 



Monthly range 47.0 



Highest mean daily 86.4, 31st 



Lowest mean daily , . . .60.4,11th 



Mean maximum 83.1 



Mean minimum 61.9 



Mean daily range 21.2 



Greatest daily range 33.=;, 6th 



Least daily range 9.0,11th 



HumidKy. 



Mean dew point ■ 63.9 



Mean force of vapor 764 



Mean relative humidity 79.4 



Precipitation. In inches. 



Total precipitation, in inches 3.36 



Number of days on which .01 inch or more 

 rain fell S 



*Temperature in ground shelter. 

 **Reduced to freezing and sea-level. 



Wind. 



Total movement 2133 m 



Greatest daily movement 242m, 19th 



Least daily movement 5m, 17th 



Mean daily movement 68. 8 m 



Mean hourly velocity 2.9 m 



Maximum pressure per square foot, lo.o lbs = 



44m per hour, i8th, 10 P, S.S.W. 

 Maximum velocity for 5 minutes 24m per 



hour, 19th, 2:30 p, S.S.W. 

 Prevailing direction. Southwest. 



Summary. 



South Southwest 26 per cent 



Southwest 23 " " 



Other directions 51 " " 



Weather. 



Mean cloudiness observed .... 48 per cent 

 Total cloudiness recorded by the Sun 



Thermometer . . 177 hours = 38 per cent 



Number of clear days 5 



Number of fair days 22 



Number of cloudy days 4 



Bright Sunshine. 



Number hours recorded, 2S5 hrs, ^= 62 per cent. 

 Rain, 2d, gth, nth, 12th, 13th, 14th, 15th, 



17th, iSth, 19th, 2ist, 24th, 29th. 

 Thunder and Lightning. I5tli, 17th, 21st, 



24th. 

 Hail, 2ist. 

 Gales, 35 or more miles per hour. 35m, 17th, 



W.: 44m, 18th, S.S.W.: 36m. iqth, S. 



