68 BEPOKT— 1892. 



Report of the Committee, consisting o/Lord McLaren (Ghairman)^ 

 Professor Crum Brown (Secretary), Dr. John Murray, Dr. 

 A. BucHAN, the Hon. Ralph Abercrombie, and Professor Cope- 

 land, appointed for the purpose of co-operating with the Scottish 

 Meteorological, Society in making Meteorological Observations on 

 Ben Xevis. {Drawn up by Dr. A. Buchan.) 



During the past year the bourly eye observations by night and by day 

 Lave been made at the Ben ^N'evis Observatory vritbont interruption hj 

 ]\[r. Oinond and the assistants. At the Low Level Observatory at Fort 

 William, the continuous registration and other observations have been 

 also successfully carried on as detailed in last year's report. 



The Directors have been again indebted to Mr. R. C. Mossman, 

 F.R.S.E., Mr. Drysdale, M.A., Mr. Craig, Mr. H. F. Rankin, and Mr. 

 Stewart, B.Sc, from Profes.sor Tail's Laboratory, who have generously 

 given their services as ol).servers for periods varying from four to eight 

 weeks during the winter and summer mouths, thus extending much- 

 needed relief to the regular members of the observing staff. 



For the year 1891 the following were the monthly mean and extreme 

 pressures, temperatures, hours of sunshine, amounts of rainfall, number 

 of fair days, or days of less than 001 inch of rain, at the Observatory, the 

 mean pressures at the top of the Ben bein? reduced to .32° F. only, while 

 those at Fort William are reduced to 32° and sea-level (see table next 

 page) :— 



The mean temperature of the whole year at Fort William was 47°-0, 

 being 0°-2 under the mean of previous years. This was the deficiency 

 in the temperature of IS'Jl over a large district surrounding Fort William. 

 On ihe other hand, the mean temperature at the top of the mountain was 

 31°'3, or 0°3 above the average of the year. The mean temperature at 

 the top as compared with the bottom of the mountain was thus half a 

 degree relatively warmer, and it may be noted that this excess of the 

 annual temperature held good in insular situations to the west and south- 

 west from Barrahead to Islay. 



The lowest mean monthly temperature occurred at both Observatories 

 in IMarch, the mean at the top being 2U°0 which was also the mean for 

 January 1^86, this being the lowest monthly mean since the Observa- 

 tory was opened. The highest monthly mean at the top was 43°-l in 

 June, and at Fort William 57°7, also in June. The general character 

 of the weather for the year was anti-cyclonic, with therefore a large 

 amount of sunshine, and for the time of the year a small difference in 

 the temperatures at the two Observatories. The temperature of February 

 was very high, and the weather exceptionally fine. At Fort William 

 temperature was 4°-l above the average, but at the top the average was 

 exceeded by 7°-5. This was by far the mildest winter n.onth hitherto 

 experienced by the observers. The weather was largely anti-cyclonic, and 

 on many occasions the atmosphere Avas unusually dry, and temperatures 

 were higher at the top than at Fort William at the same time. Conse- 

 quently the difference between the mean temperatures at the top and 

 bottom was unprecedentedly small, being indeed only approached in this, 

 res I ect by the singularly fine month of June 1887. 



The maximum temperature for the year wan 64°-9 at the to|., and 

 79°-9 at Fort William, both in June; and in Febinarv temperatures of 



