222 



REPORT — 1897, 



mountain 14°-2 is the highest minimum temperature of any year since the 

 Observatory was established. 



As regards extremes of temperature the difference between the two 

 maxima was greatest in May, when it was 22° -0, and least in December, 

 when it was 12°'6 ; and the difference between the two minima was 

 greatest in Februai-y, when it was 16°-8, and least in December, when it 

 was only 7°'8. 



The registrations of the sunshine recorder at the top show 756 hours 

 out of a possible 4,470 hours, being 61 hours more than in 1895. This 

 equals 17 per cent of the possible sunshine. The maximum was 222 hours 

 in May, being the highest hitherto recorded in any month except in June 

 1888, when the number of hours of clear sunshine was 250. The 

 minimum was 23 hours in December, no higher monthly minimum having 

 yet been recorded in any year. At Fort William the number of hours for 

 the year was 1,036, being 96 hours fewer than in 1895. This great 

 difference in favour of the top was due to a greater prevalence of anti- 

 cyclones during 1896, when clearer weather prevails at the top than at the 

 foot of the mountain. The maximum was 231 hours in May and the 

 minimum 17 in January and again in December. As the number of 

 hours of possible sunshine at Fort William is 3,497, the sunshine of 1896 

 was 30 per cent, under the possible. 



In the subjoined Table are given for each month the lowest hygro- 

 metric readings : — 



Table IV, 



Of these lowest monthly humidities the lowest occurred on March 12, 

 when the dew-point was — 22°-9, the elastic force of vapour -014 inch, 

 and relative humidity 11. Very low humidities also occurred in January, 

 February, and November. No low humidities were recorded in Sep- 

 tember, the lowest being on the 6th, when the dew-point was 35-7, and 

 the humidity 61, and in this month the sunshine was small, being only 

 29 hours, which is the smallest recorded in this month since 1885, when 

 only 25 hours were recorded. 



At the Ben Nevis Observatory the mean percentage of cloud covering 

 the sky was 83, which is the average, the maximum being 92 in March 

 and April and the minimum 56 in May ; and at Fort William the mean 

 was 77, the maximum being 87 in February and the minimum 54 in May. 

 It will be noted that in the anticy clonic months of January, February, May, 

 and November, the sky at the top was much more clear of cloud as com- 

 pared with the foot of the mountain than is usually the case. 



The mean rainband (scale 0-8) observation at the top was 2*3 for tlie 

 year, the highest being 3-3 in July, and the lowest 1-6 in November ; and 

 at Fort William 4-0 for the year, the highest being 5^4 in September, and 

 the lowest 3-4 in October. 



