METEOROLOGICAL OBSERVATORY 



OF THE 



Hatch Experiment Station 



MASSACHUSETTS AGRICULTURAL COLLEGE 



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



Height of haromder above ground, 51 ft. Above sea level, 27J.J ft. 

 Height of Wind Itistniments 72 ft. 



BULLETIN No. 21 I. 



JULY, I906. 



MONTHLY SUMMARY. 



Pres$ure. In inches. 



Maximum reduced to freezing, 30.17, 6th, S A. 

 Minimum reduced to freezing, 29.28, 30th, 3 p. 

 Reducedt maximum reading, 30.46, 6th, 8 a. 

 Reducedt minimum reading, 29.56, 30th, 3 p 



Mean semi-daily reduced, 29.980 



Montiily range 0.90 



*Air Temper at lire. In Degrees Fahr. 



Highest 88.5, 17th, 2:30 p. 



Lowest, 45-0, 7th, 5 A. 



Mean hourly, 7o-i 



Mean of means of max. and min 71. i 



Mean sensible (wet bulb), 65.4 



Monthly range, 43-5 



Highest mean daily, 76.4,22nd 



Lowest mean daily, . . . • 63.5, 7th 



Mean maxinmm 81. 8 



Mean minimum, 60.3 



Mean daily range 21.5 



Greatest daily range, 33.0, 7th 



Least daily range, 9.5, 21st, 25th 



Buniidity. 



Mean dew point, 63.1 



Mean force of vapor, 71 5 



Mean relative humidity, 82.4 



Precipitation. In inches. 



Total precipitation, 3.45 



Number of days on which .01 inch or more 

 rain or melted snow fell 12 



* Temperature in gfround shelter. 

 t Reduced to freezing and sea-level. 



Wind. 



Total movement, 3773 m. 



Greatest daily movement, .... 343 m., 3C'th 



Least daily movement, 37 m., 14th 



Mean daily movement, 122 ni. 



Mean hourly velocity, 5.1 ni. 



Maximum pressure per square foot, 6.5 lbs.= 

 36 m. per hour, 4th, 12 m., S.W. 



Maximum velocity for 5 minutes, 30 m. per 

 hour 17th, 3:30 P., S.W. 



Prevailing Direction, South, Southeast. 



Summary. 



South, 26 per cent. 



South, Southeast, 16 " " 



Southeast, . . • 13 " " 



Northwest, 10 " " 



Other directions, 35 " " 



Weather. 



Mean cloudiness observed, . . . .53 per cent. 



Total cloudiness recorded by the Sun Ther- 

 mometer, i84hrs.=40 per cent. 



Number of clear days, 5 



Number of fair days, 21 



Number of cloudy days, 5 



Bright Snnahine, 



Number of hours recorded, . . 278 lirs.=6o)< 



Rain, ist, 2d, 3d, 4th, 9th, loth, 15th, 17th, 



18th, 20th, 2ist, 23rd, 24th, 26th, 2Sth, 29th, 



30th, 31st. 



Oales, 35 miles or more per hour, 36 m, 4th, 



S.W ; 35 m, 17th, S W. 

 Thunder and iigr/j^ntngr, loth, 17th, 18th, 



20th, 2ist, 2Sth, 29th, 31st. 



