METEOROLOGICAL OBSERVATORY 



OF THE 



Hatch Experiment Station 



MASSACHUSETTS AGRICULTURAL COLLEGE, 



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



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

 Height of Wind I?istruments 72 ft. 



BULLETIN No. 2 13. 



SEPTEMBER, 1906. 



MONTHLY SUMMARY. 



treasure. In inches. 

 .Vlaxiinum reduced to freezing, 30.20, i6th,9A.' 



25th, S A. 

 Minimum reducedto freezing, . 29.1S, 3d, n A. 

 Reduced! maximum reading, 30.50, 16th, 9 a.; 



25th, 8 a. 

 Keducedt minimum reading, . 29.47, 3d, 11 A. 



Mean semi-daily reduced, 30.09° 



Monthly range, ''Oj 



*Air Temperature. In Degrees Fahr. 



Highest, 91.0, iSth, 3:30?. 



Lowest 31.5. 25th, 6:30 A. 



Mean hourly, 64.0 



Mean of means of max. and niin., .... 63.S 



Mean sensible (wet bulb), ■ . 5S.1 



Monthly range, 59-5 



Highest mean daily, 74.5,19th 



Lowest mean daily, 49.5, 25th 



Mean maximum, 7^.3 



Mean minimum, 5'-2 



Mean daily range, 25.1 



Greatest daily range, 38-Ot iSth 



[-east daily range, 3.0, 22d 



Mutniditi/. 



Mean dew point 55-2 



Mean force of vapor, 566 



Mean relative humidity, 80.1 



frecipitntion. In inches. 



Total precipitation, 2.59 



Numljer of days on which .01 inch or more 

 rain or melted snow fell 



* Temperature in ground shelter, 

 t Reduced to freezing and sea-level. 



tVind. 



fotal movement, 4249 m. 



Greatest daily movement, 345 m., 3d 



Least daily movement, ... 50 m., loth, 22d 



Mean daily movement 142 m. 



Mean hourly velocity, 5 9 m. 



Maximum pressure per square foot, 4.5 Ibs.= 

 30 m. per hour, 23d, 12 p., W.N.W. 



Maximum velocity for 5 minutes, 24 m. per 

 hour 3d, 4 p., VV. 



Prevailing Direction, West, Southwast. 



Summary. 



South, 27 per cent. 



Northwest, 13 " " 



North Northwest, 13 " " 



Other directions, 47 " " 



Weather. 



Mean cloudiness observed, .... 32per cent. 



Total cloudiness recorded by the Sun Ther- 

 mometer, .... ii9hrs.=32 per cent. 



Number of clear days, 15 



Number of fair days, iC' 



Number of cloudy days, 5 



liright Sunshine. 



Number of hours recorded, . . 254 lirs.=68* 



Rain, 3d, 12th, 13th, 20th, 21st. 22d, 27th, 

 29th, 30th. 



dales, 35 miles or more per hour, none. 

 Thunder and Ijlghtning, 12th, 14th. 

 Moderate Frost, 2;th. 



