34 



EEPORT 1887. 



Report of the Committee, consisting of Professor Crum Brown 

 {Secretary), Mr. Milne Home, Mr. John Murray, Lord McLaren, 

 and Mr. Buchan, appointed for the purpose of co-operating ivith 

 the Scottish Meteorological Society in making Meteorological 

 Observations on Ben Nevis. 



The observing work by Mr. Omond and his assistants of the Ben Nevis 

 Observatory for the past yetxr has been carried on with the same intelli- 

 gence, enthusiasm, and completeness as in previous years, none of the 

 hourly observations, by night and by day, inside and outside the observa- 

 tory having been omitted down to the close of last mouth, except the 

 outside observations of temperature on two of the hours of December 8, 

 when the weather was too stormy to be faced. The live daily observa- 

 tions at the sea-level station at Fort William have also been made with 

 the greatest regularity. 



For the year 1886 the folio wiug were the mean pressures and temper- 

 atures at the Ben Nevis Observatory and at Fort William : — 



Mean, Pressures in Inches. 



The pressures at Fort William are reduced to 32° and sea level; those 

 at the observatory only to 32°. 



With the two exceptions of October and November, the temperature 

 at Fort William was every month below its normal. The extreme de- 

 partures from the normal were December 4°-?, January 3°'4, and Feb- 

 ruary 3°'9 under, and, on the other hand, October 2°'6 above the normal. 

 The annual mean 4-5''-3 was 1°'8 below the average of the twenty-four 

 years ending 1880. 



Atmospheric pressure at Fort William was very nearly the normal on 

 the mean of the year, being only 0012 inch under it. 



The maximum pressure for the year at the observatory was 26'093 

 inches on November 24, and the minimum 23-454 inches on December 8, 

 during the memorable storm that swept over the country at that time. 

 A still lower pressure, viz., 23'17o inches, was observed on January 26, 

 1884, when pressure at 32° and sea level fell at Ochtertyre, Perthshire, to 

 27'333 inches ; and as the centre of this great storm passed only a short 

 way to the south of the observatory, this may be considered as the lowest 

 pressure likely to be noted at the observatoiy. 



The maximum temperature for the year was •!>5°'8 in September, and 

 the lowest 8°'4 in December, thus giving an absolute range of 47°-4. 



