No. 4.] ^lASSACHUSETTS WEATHEK. 



XXV 



Meteorological Observatory of the Hatch Experi- 

 ment Station (Massachusetts Agricultural Col- 

 lege), A]VIHERST. 



Annual Summary for 1899. 



Pressure {in Inches). 



Maximum reduced to freezing, 30.57, Jan- 

 uary 2, 9 A.M. 



Minimum reduced to freezing, 28.79, De- 

 cember 24, 8 P.M. 



Maximum reduced to freezing and sea 

 level, 30.92, January 2, 9 a.m. 



Minimum reduced to freezing and eea 

 level, 29.10, December 2-t, 8 P.M. 



Mean reduced to freezing and sea level, 

 30.011. 



Annual range, 1.82. 



Air Temperature (in Degrees F.).* 



Highest, 93.0, June 5, 3 p.m. 

 Lowest, — 21.5, January 2, 6 a.m. 

 Mean, 46.8. 



Mean of means of max. and min., 47.2. 

 Mean sensible (wet bulb), 43.7. 

 Annual range, 114.5. 

 Higbest mean daily, 81.5, June 6. 

 Lowest mean daily, — 0.5, February 11. 

 Mean maximum, 57.8. 

 Mean minimum, 36.6. 

 Mean daily range, 21.2. 

 Greatest daily range, 47.0, April 29. 

 Least daily range, 4.5, IMarch 15, Novem- 

 ber 15, December 5. 



JTumiditi/. 

 Mean dew point, 40.1. 

 Mean force of vapor, .420. 

 Mean relative humidity, 75.6. 



Wind. — Prevailing Direction West, Soztth- 



tvest. Summary {Per Cent). 

 North, 18. 

 North-west, 15. 

 South-south-west, 12. 

 South-west, 11. 

 South, 10. 

 West, 10. 



Other directions, 24. 

 Total movement, 47,110 miles. 

 Greatest daily movement, 449 miles, Feb- 

 ruary 13. 



Least daily movement, 4 miles, December 



18. 

 Mean daily movement, 129 miles. 

 Mean hourly velocity, 5.2 miles. 

 Maximum pressure, per square foot, 22 



pounds = 66 miles per hour, March 7, 



12 m., N.E. 



Precipitation {in Inches). 



Total precipitation, rain or melted snow, 



41.49. 

 Number of days on which .01 or more 



rain or melted snow fell, 110. 

 Snow total, in inches, .52. 



Weather. 

 Mean cloudiness observed, 54 per cent. 

 Total cloudiness recorded by sun ther- 

 mometer, 2,210 hours ^.50 per cent. 

 Number of clear days, 81. 

 Number of fair days, 139. 

 Number of cloudy days, 135. 



Bright Sunshine. 



Number of hours recorded, 2,245 = 50 per 

 cent. 



Dates of Frosts. 

 Last, May 4. 

 First, September 14. 



Dates of Snow. 

 Last, April 16. 

 First, November 12. 

 Total days of sleighing, 51. 



Gales of SO or More Miles per Hour. 

 January 7, 52 miles, N.W. ; January 15, 60 

 miles, N.W. ; January 27, 64 miles, 

 N.W.; February 10, 51 miles, W.; 

 February 13, 55 miles, N. ; March 7, 66 

 miles, N.E.; March 20, 62 miles, N.; 

 March 29, 61 miles, N.W. ; March 30, 53 

 miles, W. ; December 12, 56 miles, S.W. 



J. E. OSTRANDER, Meteorologist. 

 A. A. :Monahan, Observer. 



Temperature in ground shelter. 



