METEOROLOGICAL OBSERVATORY 



OF THE 



Hatcli Experiment Station, 



MASSACHUSETTS AGRICULTURAL COLLEGE, 



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



Height of instruments above ground, 51 ft. Above sea level, 260 ft. 



BULLETIN No. 25. 



JANUARY, 1891. 



MONTHLY SUMMARY. 



fressufe. Jn Indies. 

 Actual inaximuni reading, . 30.315, lOtli, 10 P. 

 Actual niiuinium reading, . . 28.40, I'ith, fi .v. 



Mean reiluceil to sea level, 29.958 



Moutlily I'ange, 1.915 



*Air Temperature. In Degrees Falir. 



Highest ')().o;'ri. 



Lowest, 6. ;— 0.5 



Mean, 27.6; 26.4 



.Monthly Range 44.5; 52.5 



Highest mean daily, 41.7; 41.8 



Lowest mean daily 14.3; 105 



Mean maximum 33.6; 36 



Mean minimum 21.3; 16.8 



Mean daily range 12.3; 19.2 



Greatest daily range, 29.5 ; 36. 



Least daily range 4; 7.5 



Hutniditi/. 



Mean dew point, 20.7 



Mean force of vapor 1707 



Mean relative humidity, 72.2 



Wind. 



Prevailing Directions. 



North, 31 per cent. 



North West, ........... 15 " " 



South South West, 14 " 



.South 12 " " 



Other dii-ections 28 " " 



Total movement, 4954 m. 



Greatest daily movement, .... 345 m., 18th 

 Least daily movement, 3 m., 1st 



Mean daily movement, 159.8 m. 



Mean hourly velocity, 6.7 m. 



Maximum pressure per sijuare foot,16^1bs.— 

 57 m. per hour, 22d, at 3 P. M. 



* I'recipitntion. In inches. 



Total precipitation, 4.75; 0.75 



Weather. 

 Mean cloudiness observed, . . . 61 per cent. 



Number of clear days 11 



Number of cloudy days 13 



Number of fair days 7 



Total cloudiness recoriled by the Sun Ther- 

 mometer, 172 hours or 58 per ceut. 

 Number of days on which .01 inch or more 



rain or snow fell, 13 



Depth of snow, iu inches, on ground at close 

 of month, 6 



Sright Sunshine. 



Number of Hours recorded 126.1 



Snow, 1st, 5th, 6th, 14tli, 17th, 18th, 2.5th. 

 27th, 29th, 31st. 



Total Fall in inches, 173 



Rain, 1st. 2d, 11th, 12th, 17th, 18th, 21st, 22d, 

 23d, 29th, 31st. 



Hail, 17th, 18th. 



Thunder and Ziightninf/ , 2d. 



Mean Ozone, 48 per cent. 



Halos. 



Solar, 4th, 3l8t 



Lunar 15th, 23d 



Lunar coronae, 14th, 18th, 19th 



Galen, of .50 or more miles per hour, 53, Vi., 

 i2th; 50, u. w., 14th; 57, s. w., 22d. 



'Tlic (irst figures denote readings .at top of tower, tlie secoml at base. 



